#include <u.h>#include <libc.h>#include <fcall.h>#include <avl.h> #include "dat.h"#include "fns.h" static voidlrudel(Blk *b){	if(b == fs->chead)		fs->chead = b->cnext;	if(b == fs->ctail)		fs->ctail = b->cprev;	if(b->cnext != nil)		b->cnext->cprev = b->cprev;	if(b->cprev != nil)		b->cprev->cnext = b->cnext;	b->cnext = nil;	b->cprev = nil;		} voidlrutop(Blk *b){	qlock(&fs->lrulk);	/*	 * Someone got in first and did a	 * cache lookup; we no longer want	 * to put this into the LRU, because	 * its now in use.	 */	bassert(b, b->magic == Magic);	bassert(b, checkflag(b, 0, Bstatic));	if(agetl(&b->ref) != 0){		qunlock(&fs->lrulk);		return;	}	lrudel(b);	if(fs->chead != nil)		fs->chead->cprev = b;	if(fs->ctail == nil)		fs->ctail = b;	b->cnext = fs->chead;	fs->chead = b;	rwakeup(&fs->lrurz);	qunlock(&fs->lrulk);} voidlrubot(Blk *b){	qlock(&fs->lrulk);	/*	 * Someone got in first and did a	 * cache lookup; we no longer want	 * to put this into the LRU, because	 * its now in use.	 */	bassert(b, b->magic == Magic);	bassert(b, checkflag(b, 0, Bstatic));	if(agetl(&b->ref) != 0){		qunlock(&fs->lrulk);		return;	}	lrudel(b);	if(fs->ctail != nil)		fs->ctail->cnext = b;	if(fs->chead == nil)		fs->chead = b;	b->cprev = fs->ctail;	fs->ctail = b;	rwakeup(&fs->lrurz);	qunlock(&fs->lrulk);} voidcacheins(Blk *b){	u32int h; 	bassert(b, b->magic == Magic);	h = ihash(b->bp.addr) % fs->cmax;	qlock(&fs->lrulk);	traceb("cache", b->bp);	bassert(b, checkflag(b, 0, Bstatic|Bcached));	setflag(b, Bcached, 0);	bassert(b, b->hnext == nil);	b->cached = getcallerpc(&b);	b->hnext = fs->bcache[h];	fs->bcache[h] = b;	qunlock(&fs->lrulk);} static voidcachedel_lk(vlong addr){	Blk *b, **p;	u32int h; 	if(addr == -1)		return; 	Bptr bp = {addr, -1, -1};	tracex("uncache", bp, -1, getcallerpc(&addr));	h = ihash(addr) % fs->cmax;	p = &fs->bcache[h];	for(b = *p; b != nil; b = b->hnext){		if(b->bp.addr == addr){			/* FIXME: Until we clean up snap.c, we can have dirty blocks in cache */			bassert(b, checkflag(b, Bcached, Bstatic)); //Bdirty));			*p = b->hnext;			b->uncached = getcallerpc(&addr);			b->hnext = nil;			setflag(b, 0, Bcached);			break;		}		p = &b->hnext;	}}voidcachedel(vlong addr){	qlock(&fs->lrulk);	Bptr bp = {addr, -1, -1};	tracex("uncachelk", bp, -1, getcallerpc(&addr));	cachedel_lk(addr);	qunlock(&fs->lrulk);} Blk*cacheget(vlong addr){	u32int h;	Blk *b; 	h = ihash(addr) % fs->cmax;	qlock(&fs->lrulk);	for(b = fs->bcache[h]; b != nil; b = b->hnext){		if(b->bp.addr == addr){			holdblk(b);			lrudel(b);			b->lasthold = getcallerpc(&addr);			break;		}	}	qunlock(&fs->lrulk); 	return b;} /* * Pulls the block from the bottom of the LRU for reuse. */Blk*cachepluck(void){	Blk *b; 	qlock(&fs->lrulk);	while(fs->ctail == nil)		rsleep(&fs->lrurz); 	b = fs->ctail;	bassert(b, b->magic == Magic);	bassert(b, agetl(&b->ref) == 0);	if(checkflag(b, Bcached, 0))		cachedel_lk(b->bp.addr);	bassert(b, checkflag(b, 0, Bcached));	lrudel(b);	aswapl(&b->flag, 0);	b->lasthold = 0;	b->lastdrop = 0;	b->freed = 0;	b->hnext = nil;	qunlock(&fs->lrulk); 	return  holdblk(b);}