free inode only when noone is holding a pointer to it.  should fix open-unlink- read problem, but untested
free inode only when noone is holding a pointer to it.  should fix open-unlink-
read problem, but untested

lorenzo-stoakes/haxv6,gmy987/xv6,WeiranFang/cs518hw3,roygoldman/xv6-fsprot,descent/xv6,fintler/xv6,Royvaknin29/OS_Ass1,jeffallen/xv6,nullpo-head/xv6-mips,justodiaz/xv6,KushOza/hw2,t3rm1n4l/xv6,avana002/xv6,raman162/CS450,i/xv6,KushOza/hw2,AskDrCatcher/xv6,OrangeTide/xv6-public,SanchayanMaity/xv6-cs450,gw/xv6,gburd/xv6,sigma-random/xv6,AndreiRO/xv6,Y-liulian/xv6-public,BMJHayward/xv6-public,rafamanzo/ep2-so-xv6,MrHohn/CS-OperatingSystem-hw2,pelhamnicholas/xv6,run/xv6,gco/xv6,bngabonziza/xv6-1,orenherman/xv6-clone,jmatth/xv6,tinti/xv6-ubuntu,gco/xv6,Cealestus/cmpt332Assignment1,ahorn/xv6,5kg/xv6,firstblade/xv6,t3rm1n4l/xv6,gzpan123/xv6,galbenor/os162-4,bowlofstew/sv6,liadgi/os163,lishuwnc/Xv6,voytovichs/xv6-public,liorderei/OS_Class,junxu/xv6,tamlok/xv6,guilleiguaran/xv6,arcbbb/xv6,kongming92/6828-xv6,logangorence/xv6-public,AskDrCatcher/xv6,imagine4077/xv6-public,chrisdew/xv6,DuskDragon/xv6,varunk08/xv6,walafc0/xv6,expertsnipo/xv6,UIKit0/xv6-1,ihciah/xv6,liyinhgqw/xv6,aclements/sv6,tenstep/xv6,sdimitro/xv6,jmatth/xv6,Laaia/RT-xv6,alex0906093/xv6,TheMatrixShibe/tmsv6,liyinhgqw/xv6,siddharthv/xv6,arajago6/Axv6_One,RicardoParizotto/xv6---stride-scheduling,MrHohn/cs518hw2,arturosevilla/xv6-turi,johnson-li/xv6-homework,xujunhai1991/xv6,UIKit0/Xv6,tehgeekmeister/xv6,shtyd/xv6-lua,myl2821/xv6-fork,humphreyja/Xv6,niral28/hw1,jeffallen/xv6,SanchayanMaity/xv6-cs450,SanchayanMaity/xv6-cs450,baboofei/v6rt,CKost/Authorization,niral28/hw1,gnosis23/xv6,MrHohn/cs518hw3,s-rah/xv6-permissions,UIKit0/xv6-1,juroland/xv6,svdamani/xv6,ihciah/XV6-OS,Laaia/RT-xv6,bowlofstew/sv6,gnosis23/xv6,chnpmy/xv6,niral28/hw1,phf/xv6-public,shining-yang/xv6,pablogventura/xv6-public,gzpan123/xv6,SarthakCodes/xv6,williamsandrew/xv6,SajadAzami/xv6-pm,ihciah/XV6-OS,yum185/assign1_partA,kongming92/6828-xv6,walafc0/xv6,rafamanzo/ep4-so,rafamanzo/ep2-so-xv6,danluu/Xv6,panks/Xv6,shyandsy/xv6,voytovichs/xv6-public,ManaPoustizadeh/OS-finalProject,danrods/xv6Hacks,juroland/xv6,sdimitro/xv6,lolosssss/Xv6,shadowfax-ring/mit-xv6,shining-yang/xv6,louisje/xv6,aquamme/xv6,CHRISTOPHERDIEHL/xv6,gmy987/xv6,prashantkhurana/OS,shyandsy/xv6,film42/xv6,juroland/xv6,dswann5/os_assignment_3,prashantkhurana/OS,DuskDragon/xv6,arianvp/xv6,UIKit0/Xv6,ZheyuJin/xv6_reading,lenw/xv6-public,tamlok/xv6,avana002/xv6,HawxChen/Offical-Version-xv6,gw/xv6,SarthakCodes/xv6,BMJHayward/xv6-public,nwf/xv6-public,lenw/xv6-public,danluu/Xv6,ahorn/xv6,s-rah/xv6-permissions,codelabs-ch/xv6-muen,siddharthv/xv6,ahorn/xv6,v1ta/xv6,roygoldman/xv6-sem,kingsizeme/xv6,romanzhg/xv6,preshshah/xv6,shadowfax-ring/mit-xv6,run/xv6,jeffallen/xv6,walafc0/xv6,lorenzo-stoakes/haxv6,dswann5/os_assignment_3,pekopeko1/xv6-code,arcbbb/xv6,meilank/CS416-hw1,ManaPoustizadeh/OS-finalProject,nwf/xv6-public,svdamani/xv6,penguiner/xv6,yubai/ksm_xv6,gnudeep/xv6,meilank/CS416-hw1,lord021/Assignment1,CHRISTOPHERDIEHL/xv6,firstblade/xv6,pablogventura/xv6-public,leenjewel/xv6_learn,rafamanzo/ep4-so,lord021/Assignment2,avana002/xv6,sometimesfood/xv6-public,MatanGilead/myxv6,ThomasDq/xv6OS,davidbalbert/xv6,Mifnight/xv6-public,chnpmy/xv6,v1ta/xv6,GautamV/xv6,HugoTian/xv6,nullpo-head/xv6-mips,arcbbb/xv6,niral28/hw1,williamsandrew/xv6,romanzhg/xv6,jmatth/xv6,wangxiayang/xv6,Laaia/RT-xv6,baboofei/v6rt,svdamani/xv6,pelhamnicholas/xv6,PINK-FL0YD/xv6-public,chyka-dev/xv6-public,liorderei/OS_Class,liadgi/os163,prashantkhurana/OS,prashantkhurana/OS,emaadmanzoor/xv6,bngabonziza/xv6-public,SanchayanMaity/xv6-cs450,lolosssss/Xv6,sometimesfood/xv6,f13mash/xv6,logangorence/xv6-public,aquamme/xv6,Mifnight/xv6-public,MrHohn/CS-OperatingSystem-hw3,vicionator/XV6,tinti/xv6-ubuntu,gw/xv6,MatanGilead/myxv6,yubai/ksm_xv6,voytovichs/xv6-public,pekopeko1/xv6-code,preshshah/xv6,wasabiz/xv6,wkatsak/xv6,kongming92/6828-xv6,codelabs-ch/xv6-muen,SajadAzami/xv6-pm,cpehle/xv6,vicionator/XV6,arianvp/xv6,rajma996/xv6,pekopeko1/xv6-code,shyandsy/xv6,rlok3000/xv6,sdharan/xv6-rcu,lord021/Assignment2,eewayhsu/xv6,oskarth/xv6,aclements/sv6,meilank/CS416-hw1,gzpan123/xv6,gnosis23/xv6,danrods/xv6Hacks,danrods/xv6Hacks,reutz19/xv6_ass4,guilleiguaran/xv6,MrHohn/CS-OperatingSystem-hw3,AZQ1994/xv6,arturosevilla/xv6-turi,yum185/assign1_partA,tehgeekmeister/xv6,PINK-FL0YD/xv6-public,aclements/sv6,sdharan/xv6-rcu,arajago6/Axv6_One,HawxChen/Offical-Version-xv6,KushOza/hw2,meilank/CS416-hw2,kazunobu-fujii/xv6,sigma-random/xv6,PINK-FL0YD/xv6-public,WeiranFang/cs518hw3,ckkashyap/xv6,seckcoder/mirror-xv6,KushOza/hw2,liyinhgqw/xv6,garzon/xv6-public,RicardoParizotto/xv6---stride-scheduling,HugoTian/xv6,supdizh/clean_xv6,sigma-random/xv6,tehgeekmeister/xv6,supdizh/clean_xv6,alex0906093/xv6,justodiaz/xv6,wenhuizhang/xv6-public,CKost/Authorization,nullpo-head/xv6-mips,robertpd/xv6,t3rm1n4l/xv6,tamlok/xv6,myl2821/xv6-fork,sometimesfood/xv6-public,lolosssss/Xv6,bngabonziza/xv6-1,preshshah/xv6,bowlofstew/xv6-public,justodiaz/xv6,nwolovick/xv6-public,rlok3000/xv6,aclements/sv6,tenstep/xv6,sdharan/xv6-rcu,xv6-jp/xv6,CHRISTOPHERDIEHL/xv6,khalily/xv6,panks/Xv6,oskarth/xv6,ahorn/xv6,danluu/Xv6,jgome043/tearos,OrangeTide/xv6-public,sometimesfood/xv6,preshshah/xv6,myl2821/xv6-fork,MrHohn/cs518hw2,bohaoist/xv6,emaadmanzoor/xv6,Royvaknin29/OS_Ass1,chyka-dev/xv6-public,nomadium/xv6,raman162/CS450,howerj/xv6,TheDude05/xv6,forwchen/xv6,GautamV/xv6,myl2821/xv6-fork,pablogventura/xv6-public,chrisdew/xv6,bowlofstew/sv6,descent/xv6,tehgeekmeister/xv6,maxymania/open-xv6,RicardoParizotto/xv6---stride-scheduling,laisborin/RT-xv6,romanzhg/xv6,msyksphinz/xv6-mips,techno/xv6-mist32,tlerea1/xv6,sigma-random/xv6,meilank/CS416-hw1,OrangeTide/xv6-public,Y-liulian/xv6-public,Raysmond/xv6,SarthakCodes/xv6,ckkashyap/xv6,gnudeep/xv6,shining-yang/xv6,lord021/Assignment1,roygoldman/xv6-fsprot,dswann5/os_assignment_3,nomadium/xv6,bngabonziza/xv6-1,pekopeko1/xv6,khalily/xv6,lorenzo-stoakes/haxv6,MatanGilead/myxv6,walafc0/xv6,pelhamnicholas/xv6,lord021/Assignment1,aquamme/xv6,seckcoder/mirror-xv6,f13mash/xv6,bngabonziza/xv6-1,liorderei/OS_Class,i/xv6,gmy987/xv6,imagine4077/xv6-public,AZQ1994/xv6,BMJHayward/xv6-public,roygoldman/xv6-fsprot,gburd/xv6,MrHohn/cs518hw3,eewayhsu/xv6,meilank/CS416-hw2,Mifnight/xv6-public,nwolovick/xv6-public,konyavic/xv6,imagine4077/xv6-public,gnosis23/xv6,davidbalbert/xv6,laisborin/RT-xv6,louisje/xv6,firstblade/xv6,gnudeep/xv6,arajago6/Axv6_One,Royvaknin29/OS_Ass1,codelabs-ch/xv6-muen,techno/xv6-mist32,TheDude05/xv6,leenjewel/xv6_learn,tlerea1/xv6,alex0906093/xv6,HugoTian/xv6,jsommers/xv6-public,lenw/xv6-public,Laaia/RT-xv6,nwf/xv6-public,xujunhai1991/xv6,MrHohn/CS-OperatingSystem-hw2,phf/xv6-public,AskDrCatcher/xv6,run/xv6,rajma996/xv6,robertpd/xv6,wkatsak/xv6,tamlok/xv6,eewayhsu/xv6,film42/xv6,AndreiRO/xv6,pekopeko1/xv6,phf/xv6-public,raman162/CS450,rajma996/xv6,t3rm1n4l/xv6,raman162/CS450,sometimesfood/xv6,gco/xv6,seckcoder/mirror-xv6,msyksphinz/xv6-mips,pekopeko1/xv6,ckkashyap/xv6,Royvaknin29/OS_Ass1,wenhuizhang/xv6-public,laisborin/RT-xv6,arajago6/Axv6_One,kongming92/6828-xv6,bowlofstew/sv6,ckkashyap/xv6,gburd/xv6,shyandsy/xv6,penguiner/xv6,rafamanzo/ep4-so,supr/Xv6,roygoldman/xv6-sem,BMJHayward/xv6-public,laisborin/RT-xv6,HugoTian/xv6,emaadmanzoor/xv6,nwolovick/xv6-public,gnudeep/xv6,gzpan123/xv6,yum185/assign1_partA,penguiner/xv6,techno/xv6-mist32,MrHohn/CS-OperatingSystem-hw3,ihciah/XV6-OS,UIKit0/xv6-1,i/xv6,orenherman/xv6-clone,MrHohn/cs518hw2,meilank/CS416-hw2,ThomasDq/xv6OS,svdamani/xv6,meilank/CS416-hw2,tlerea1/xv6,film42/xv6,nrahimi/xv6,WeiranFang/cs518hw3,danrods/xv6Hacks,siddharthv/xv6,leenjewel/xv6_learn,oskarth/xv6,RicardoParizotto/xv6---stride-scheduling,CKost/Authorization,humphreyja/Xv6,5kg/xv6,lord021/Assignment2,kingsizeme/xv6,bowlofstew/xv6-public,vicionator/XV6,ShakhMoves/Shakh6,reutz19/xv6_ass4,xujunhai1991/xv6,lolosssss/Xv6,lishuwnc/Xv6,lishuwnc/Xv6,i/xv6,juroland/xv6,lenw/xv6-public,garzon/xv6,bngabonziza/xv6,arianvp/xv6,Raysmond/xv6,nwf/xv6-public,robertpd/xv6,expertsnipo/xv6,leenjewel/xv6_learn,AndreiRO/xv6,GautamV/xv6,chnpmy/xv6,johnson-li/xv6-homework,kingsizeme/xv6,ihciah/XV6-OS,CHRISTOPHERDIEHL/xv6,DuskDragon/xv6,arianvp/xv6,jgome043/tearos,supdizh/clean_xv6,Y-liulian/xv6-public,s-rah/xv6-permissions,siddharthv/xv6,wkatsak/xv6,khalily/xv6,HawxChen/Offical-Version-xv6,v1ta/xv6,expertsnipo/xv6,CKost/Authorization,kingsizeme/xv6,msyksphinz/xv6-mips,jmatth/xv6,johnson-li/xv6-homework,xv6-jp/xv6,jsommers/xv6-public,aquamme/xv6,chnpmy/xv6,UIKit0/xv6-1,TheMatrixShibe/tmsv6,arturosevilla/xv6-turi,khalily/xv6,maxymania/open-xv6,nullpo-head/xv6-mips,orenherman/xv6-clone,davidbalbert/xv6,SajadAzami/xv6-pm,kazunobu-fujii/xv6,chyka-dev/xv6-public,yubai/ksm_xv6,yubai/ksm_xv6,seckcoder/mirror-xv6,eewayhsu/xv6,sometimesfood/xv6,reutz19/xv6_ass4,nomadium/xv6,nrahimi/xv6,bngabonziza/xv6-public,bngabonziza/xv6-public,f13mash/xv6,MrHohn/cs518hw2,garzon/xv6-public,emaadmanzoor/xv6,TheMatrixShibe/tmsv6,shadowfax-ring/mit-xv6,ihciah/xv6,imagine4077/xv6-public,Cheukyin/xv6,baboofei/v6rt,bngabonziza/xv6,arcbbb/xv6,yubai/ksm_xv6,Cealestus/cmpt332Assignment1,baboofei/v6rt,voytovichs/xv6-public,justodiaz/xv6,jgome043/tearos,orenherman/xv6-clone,supdizh/clean_xv6,UIKit0/Xv6,bohaoist/xv6,chrisdew/xv6,techno/xv6-mist32,pekopeko1/xv6,penguiner/xv6,jsommers/xv6-public,phf/xv6-public,s-rah/xv6-permissions,galbenor/os162-4,kazunobu-fujii/xv6,MrHohn/cs518hw3,galbenor/os162-4,bowlofstew/sv6,ManaPoustizadeh/OS-finalProject,PINK-FL0YD/xv6-public,williamsandrew/xv6,msyksphinz/xv6-mips,bngabonziza/xv6-public,rlok3000/xv6,wangxiayang/xv6,ThomasDq/xv6OS,rafamanzo/ep2-so-xv6,shining-yang/xv6,davidbalbert/xv6,roygoldman/xv6-fsprot,v1ta/xv6,sdharan/xv6-rcu,lord021/Assignment2,AskDrCatcher/xv6,louisje/xv6,reutz19/xv6_ass4,galbenor/os162-4,voytovichs/xv6-public,oskarth/xv6,5kg/xv6,sdimitro/xv6,ShakhMoves/Shakh6,MrHohn/CS-OperatingSystem-hw3,Mifnight/xv6-public,fintler/xv6,romanzhg/xv6,liadgi/os163,tinti/xv6-ubuntu,bohaoist/xv6,ThomasDq/xv6OS,rajma996/xv6,wasabiz/xv6,louisje/xv6,SajadAzami/xv6-pm,johnson-li/xv6-homework,aclements/sv6,ZheyuJin/xv6_reading,junxu/xv6,MrHohn/cs518hw3,UIKit0/Xv6,Cheukyin/xv6,lorenzo-stoakes/haxv6,shtyd/xv6-lua,arturosevilla/xv6-turi,descent/xv6,varunk08/xv6,SarthakCodes/xv6,5kg/xv6,ZheyuJin/xv6_reading,nwolovick/xv6-public,fintler/xv6,bowlofstew/xv6-public,wkatsak/xv6,ShakhMoves/Shakh6,jsommers/xv6-public,xujunhai1991/xv6,sometimesfood/xv6-public,wangxiayang/xv6,AndreiRO/xv6,dswann5/os_assignment_3,wangxiayang/xv6,MrHohn/CS-OperatingSystem-hw2,rlok3000/xv6,kazunobu-fujii/xv6,DuskDragon/xv6,jgome043/tearos,AZQ1994/xv6,supr/Xv6,TheMatrixShibe/tmsv6,WeiranFang/cs518hw3,avana002/xv6,expertsnipo/xv6,sdimitro/xv6,shtyd/xv6-lua,ManaPoustizadeh/OS-finalProject,MatanGilead/myxv6,bohaoist/xv6,OrangeTide/xv6-public,firstblade/xv6,konyavic/xv6,humphreyja/Xv6,chrisdew/xv6,Y-liulian/xv6-public,ShakhMoves/Shakh6,bowlofstew/xv6-public,vicionator/XV6,codelabs-ch/xv6-muen,junxu/xv6,robertpd/xv6,Cealestus/cmpt332Assignment1,Cealestus/cmpt332Assignment1,varunk08/xv6,forwchen/xv6,film42/xv6,run/xv6,konyavic/xv6,panks/Xv6,MrHohn/CS-OperatingSystem-hw2,lishuwnc/Xv6,TheDude05/xv6,gmy987/xv6,xv6-jp/xv6,howerj/xv6,descent/xv6,ThomasDq/xv6OS,pelhamnicholas/xv6,tlerea1/xv6,ZheyuJin/xv6_reading,bngabonziza/xv6,nomadium/xv6,gw/xv6,tehgeekmeister/xv6,AZQ1994/xv6,shtyd/xv6-lua,danluu/Xv6,Cheukyin/xv6,guilleiguaran/xv6,howerj/xv6,humphreyja/Xv6,nrahimi/xv6,gw/xv6,Cheukyin/xv6,junxu/xv6,bngabonziza/xv6,nwf/xv6-public,GautamV/xv6,guilleiguaran/xv6,garzon/xv6-public,garzon/xv6-public,yum185/assign1_partA,pekopeko1/xv6-code,supr/Xv6,sometimesfood/xv6-public,alex0906093/xv6,chyka-dev/xv6-public,shyandsy/xv6,roygoldman/xv6-sem,gburd/xv6,wenhuizhang/xv6-public,cpehle/xv6,liorderei/OS_Class,pablogventura/xv6-public,howerj/xv6,shadowfax-ring/mit-xv6,roygoldman/xv6-sem,varunk08/xv6,logangorence/xv6-public,wenhuizhang/xv6-public,garzon/xv6,CKost/Authorization