fix iget() bug that allocated in-use inode[] entries
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rtm
parent
8abe2bcf15
commit
17e3cf15ba
7 changed files with 20 additions and 61 deletions
14
Notes
14
Notes
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@ -357,7 +357,6 @@ OH! recursive interrupts will use up any amount of cpu[].stack!
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disk scheduling
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mkdir
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more than one directory content block
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sh arguments
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sh redirection
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indirect blocks
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@ -366,17 +365,10 @@ two bugs in unlink: don't just return if nlink > 0,
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is there a create/create race for same file name?
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resulting in two entries w/ same name in directory?
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namei
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return just inode
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return offset in dir where found, w/ dir locked, for unlink
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return dir locked, for mknod
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is the offset alone useful? how do I read/write it?
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test: one process unlinks a file while another links to it
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test: simultaneous create of same file
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test: one process opens a file while another deletes it
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oy, mkfs wants dir size to be last written entry, but i
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want it to be nblocks*512
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maybe fix kernel code to handle former
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wdir should use writei, to avoid special-case block allocation
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also readi
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is dir locked? probably
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2
fd.c
2
fd.c
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@ -8,6 +8,8 @@
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#include "fd.h"
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#include "spinlock.h"
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#include "dev.h"
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#include "fs.h"
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#include "fsvar.h"
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struct spinlock fd_table_lock;
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struct devsw devsw[NDEV];
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50
fs.c
50
fs.c
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@ -54,7 +54,6 @@ balloc(uint dev)
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if (b >= size)
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panic("balloc: out of blocks\n");
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cprintf ("balloc: allocate block %d\n", b);
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bp->data[bi/8] |= 0x1 << (bi % 8);
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bwrite (bp, BBLOCK(b, ninodes)); // mark it allocated on disk
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brelse(bp);
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@ -70,7 +69,6 @@ bfree(int dev, uint b)
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int ninodes;
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uchar m;
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cprintf ("bfree: free block %d\n", b);
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bp = bread(dev, 1);
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sb = (struct superblock *) bp->data;
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ninodes = sb->ninodes;
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@ -93,13 +91,14 @@ bfree(int dev, uint b)
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struct inode *
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iget(uint dev, uint inum)
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{
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struct inode *ip, *nip = 0;
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struct inode *ip, *nip;
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struct dinode *dip;
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struct buf *bp;
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acquire(&inode_table_lock);
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loop:
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nip = 0;
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for(ip = &inode[0]; ip < &inode[NINODE]; ip++){
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if(ip->count > 0 && ip->dev == dev && ip->inum == inum){
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if(ip->busy){
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@ -180,11 +179,9 @@ ialloc(uint dev, short type)
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brelse(bp);
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}
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if (inum >= ninodes) {
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if (inum >= ninodes)
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panic ("ialloc: no inodes left\n");
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}
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cprintf ("ialloc: %d\n", inum);
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dip->type = type;
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bwrite (bp, IBLOCK(inum)); // mark it allocated on the disk
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brelse(bp);
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@ -195,7 +192,6 @@ ialloc(uint dev, short type)
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static void
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ifree(struct inode *ip)
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{
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cprintf("ifree: %d\n", ip->inum);
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ip->type = 0;
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iupdate(ip);
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}
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@ -220,7 +216,7 @@ ilock(struct inode *ip)
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void
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iunlock(struct inode *ip)
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{
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if(ip->busy != 1)
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if(ip->busy != 1 || ip->count < 1)
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panic("iunlock");
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acquire(&inode_table_lock);
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@ -271,7 +267,7 @@ iput(struct inode *ip)
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if(ip->count < 1 || ip->busy != 1)
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panic("iput");
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if ((ip->count <= 1) && (ip->nlink <= 0))
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if ((ip->count == 1) && (ip->nlink == 0))
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iunlink(ip);
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acquire(&inode_table_lock);
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@ -498,8 +494,6 @@ mknod(char *cp, short type, short major, short minor)
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{
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struct inode *ip, *dp;
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cprintf("mknod: %s %d %d %d\n", cp, type, major, minor);
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if ((dp = namei(cp, NAMEI_CREATE, 0)) == 0)
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return 0;
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@ -525,24 +519,17 @@ unlink(char *cp)
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{
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struct inode *ip, *dp;
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struct dirent de;
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uint off, inum, cc;
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uint off, inum, dev;
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cprintf("unlink(%s)\n", cp);
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if ((dp = namei(cp, NAMEI_DELETE, &off)) == 0) {
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cprintf("unlink(%s) it doesn't exist\n", cp);
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if ((dp = namei(cp, NAMEI_DELETE, &off)) == 0)
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return -1;
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}
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if((cc = readi(dp, (char*)&de, off, sizeof(de))) != sizeof(de) ||
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de.inum == 0){
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cprintf("off %d dp->size %d cc %d de.inum %d",
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off, dp->size, cc, de.inum);
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dev = dp->dev;
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if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de) || de.inum == 0)
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panic("unlink no entry");
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}
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inum = de.inum;
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cprintf("dinum %d off %d de %s/%d\n",
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dp->inum, off, de.name, de.inum);
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memset(&de, 0, sizeof(de));
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if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de))
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@ -551,9 +538,7 @@ unlink(char *cp)
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iupdate(dp);
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iput(dp);
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ip = iget(dp->dev, inum);
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if(ip == 0)
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panic("unlink no inode");
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ip = iget(dev, inum);
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ip->nlink--;
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@ -568,14 +553,9 @@ link(char *name1, char *name2)
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{
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struct inode *ip, *dp;
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cprintf("link(%s, %s)\n", name1, name2);
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if ((ip = namei(name1, NAMEI_LOOKUP, 0)) == 0){
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cprintf(" failed %s does not exist\n", name1);
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if ((ip = namei(name1, NAMEI_LOOKUP, 0)) == 0)
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return -1;
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}
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if(ip->type == T_DIR){
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cprintf(" failed %s is a dir\n", name1);
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iput(ip);
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return -1;
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}
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@ -583,12 +563,10 @@ link(char *name1, char *name2)
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iunlock(ip);
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if ((dp = namei(name2, NAMEI_CREATE, 0)) == 0) {
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cprintf(" failed %s exists\n", name2);
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idecref(ip);
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return -1;
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}
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if(dp->dev != ip->dev){
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cprintf(" cross-device link\n");
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idecref(ip);
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iput(dp);
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return -1;
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@ -602,7 +580,5 @@ link(char *name1, char *name2)
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iput(dp);
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iput(ip);
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cprintf(" succeeded\n");
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return 0;
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}
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3
init.c
3
init.c
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@ -17,10 +17,7 @@ main(void)
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open("console", 1);
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open("console", 1);
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puts("init...\n");
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while(1){
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puts("running sh...\n");
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pid = fork();
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if(pid == 0){
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exec("sh", sh_args);
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2
ioapic.c
2
ioapic.c
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@ -43,7 +43,6 @@ ioapic_init(void)
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id = ioapic_read(io, IOAPIC_ID) >> APIC_ID_SHIFT;
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if (id != ioapic_id)
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panic ("ioapic_init: id isn't equal to ioapic_id\n");
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cprintf ("ioapic VER: 0x%x id %d nintr %d\n", l, id, nintr);
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for (i = 0; i < nintr; i++) {
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// active-hi and edge-triggered for ISA interrupts
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// Assume that pin 0 on the first I/O APIC is an ExtINT pin.
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@ -78,5 +77,4 @@ ioapic_enable (int irq, int cpunum)
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h &= ~IOART_DEST;
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h |= (cpunum << APIC_ID_SHIFT);
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ioapic_write(io, IOAPIC_REDTBL_HI(irq), h);
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cprintf("cpu%d: intr %d: lo 0x%x hi 0x%x\n", cpu(), irq, l, h);
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}
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7
picirq.c
7
picirq.c
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@ -22,13 +22,6 @@ irq_setmask_8259A(ushort mask)
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outb(IO_PIC1+1, (char)mask);
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outb(IO_PIC2+1, (char)(mask >> 8));
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cprintf("%d: enabled interrupts:", cpu());
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for (i = 0; i < 16; i++)
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if (~mask & (1<<i))
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cprintf(" %d", i);
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cprintf("\n");
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}
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/* Initialize the 8259A interrupt controllers. */
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@ -284,6 +284,7 @@ sys_mknod(void)
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return -1;
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nip = mknod (cp->mem + arg0, (short) arg1, (short) arg2, (short) arg3);
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if(nip)
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iput(nip);
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return (nip == 0) ? -1 : 0;
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}
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