From 17e3cf15bac0c1ac60780ce7d1d228442ff08ed9 Mon Sep 17 00:00:00 2001
From: rtm <rtm>
Date: Sun, 13 Aug 2006 15:51:58 +0000
Subject: [PATCH] fix iget() bug that allocated in-use inode[] entries
---
Notes | 14 +++-----------
fd.c | 2 ++
fs.c | 50 +++++++++++++-------------------------------------
init.c | 3 ---
ioapic.c | 2 --
picirq.c | 7 -------
syscall.c | 3 ++-
7 files changed, 20 insertions(+), 61 deletions(-)
diff --git a/Notes b/Notes
index 4bb9552..ab28ec3 100644
--- a/Notes
+++ b/Notes
@@ -357,7 +357,6 @@ OH! recursive interrupts will use up any amount of cpu[].stack!
disk scheduling
mkdir
-more than one directory content block
sh arguments
sh redirection
indirect blocks
@@ -366,17 +365,10 @@ two bugs in unlink: don't just return if nlink > 0,
is there a create/create race for same file name?
resulting in two entries w/ same name in directory?
-namei
- return just inode
- return offset in dir where found, w/ dir locked, for unlink
- return dir locked, for mknod
-
-is the offset alone useful? how do I read/write it?
-
test: one process unlinks a file while another links to it
test: simultaneous create of same file
test: one process opens a file while another deletes it
-oy, mkfs wants dir size to be last written entry, but i
- want it to be nblocks*512
- maybe fix kernel code to handle former
+wdir should use writei, to avoid special-case block allocation
+ also readi
+ is dir locked? probably
diff --git a/fd.c b/fd.c
index 25a51fb..e61cab2 100644
--- a/fd.c
+++ b/fd.c
@@ -8,6 +8,8 @@
#include "fd.h"
#include "spinlock.h"
#include "dev.h"
+#include "fs.h"
+#include "fsvar.h"
struct spinlock fd_table_lock;
struct devsw devsw[NDEV];
diff --git a/fs.c b/fs.c
index 37b964d..fbb4a8c 100644
--- a/fs.c
+++ b/fs.c
@@ -54,7 +54,6 @@ balloc(uint dev)
if (b >= size)
panic("balloc: out of blocks\n");
- cprintf ("balloc: allocate block %d\n", b);
bp->data[bi/8] |= 0x1 << (bi % 8);
bwrite (bp, BBLOCK(b, ninodes)); // mark it allocated on disk
brelse(bp);
@@ -70,7 +69,6 @@ bfree(int dev, uint b)
int ninodes;
uchar m;
- cprintf ("bfree: free block %d\n", b);
bp = bread(dev, 1);
sb = (struct superblock *) bp->data;
ninodes = sb->ninodes;
@@ -93,13 +91,14 @@ bfree(int dev, uint b)
struct inode *
iget(uint dev, uint inum)
{
- struct inode *ip, *nip = 0;
+ struct inode *ip, *nip;
struct dinode *dip;
struct buf *bp;
acquire(&inode_table_lock);
loop:
+ nip = 0;
for(ip = &inode[0]; ip < &inode[NINODE]; ip++){
if(ip->count > 0 && ip->dev == dev && ip->inum == inum){
if(ip->busy){
@@ -180,11 +179,9 @@ ialloc(uint dev, short type)
brelse(bp);
}
- if (inum >= ninodes) {
+ if (inum >= ninodes)
panic ("ialloc: no inodes left\n");
- }
- cprintf ("ialloc: %d\n", inum);
dip->type = type;
bwrite (bp, IBLOCK(inum)); // mark it allocated on the disk
brelse(bp);
@@ -195,7 +192,6 @@ ialloc(uint dev, short type)
static void
ifree(struct inode *ip)
{
- cprintf("ifree: %d\n", ip->inum);
ip->type = 0;
iupdate(ip);
}
@@ -220,7 +216,7 @@ ilock(struct inode *ip)
void
iunlock(struct inode *ip)
{
- if(ip->busy != 1)
+ if(ip->busy != 1 || ip->count < 1)
panic("iunlock");
acquire(&inode_table_lock);
@@ -271,7 +267,7 @@ iput(struct inode *ip)
if(ip->count < 1 || ip->busy != 1)
panic("iput");
- if ((ip->count <= 1) && (ip->nlink <= 0))
+ if ((ip->count == 1) && (ip->nlink == 0))
iunlink(ip);
acquire(&inode_table_lock);
@@ -498,8 +494,6 @@ mknod(char *cp, short type, short major, short minor)
{
struct inode *ip, *dp;
- cprintf("mknod: %s %d %d %d\n", cp, type, major, minor);
-
if ((dp = namei(cp, NAMEI_CREATE, 0)) == 0)
return 0;
@@ -525,24 +519,17 @@ unlink(char *cp)
{
struct inode *ip, *dp;
struct dirent de;
- uint off, inum, cc;
+ uint off, inum, dev;
- cprintf("unlink(%s)\n", cp);
-
- if ((dp = namei(cp, NAMEI_DELETE, &off)) == 0) {
- cprintf("unlink(%s) it doesn't exist\n", cp);
+ if ((dp = namei(cp, NAMEI_DELETE, &off)) == 0)
return -1;
- }
- if((cc = readi(dp, (char*)&de, off, sizeof(de))) != sizeof(de) ||
- de.inum == 0){
- cprintf("off %d dp->size %d cc %d de.inum %d",
- off, dp->size, cc, de.inum);
+ dev = dp->dev;
+
+ if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de) || de.inum == 0)
panic("unlink no entry");
- }
+
inum = de.inum;
- cprintf("dinum %d off %d de %s/%d\n",
- dp->inum, off, de.name, de.inum);
memset(&de, 0, sizeof(de));
if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de))
@@ -551,9 +538,7 @@ unlink(char *cp)
iupdate(dp);
iput(dp);
- ip = iget(dp->dev, inum);
- if(ip == 0)
- panic("unlink no inode");
+ ip = iget(dev, inum);
ip->nlink--;
@@ -568,14 +553,9 @@ link(char *name1, char *name2)
{
struct inode *ip, *dp;
- cprintf("link(%s, %s)\n", name1, name2);
-
- if ((ip = namei(name1, NAMEI_LOOKUP, 0)) == 0){
- cprintf(" failed %s does not exist\n", name1);
+ if ((ip = namei(name1, NAMEI_LOOKUP, 0)) == 0)
return -1;
- }
if(ip->type == T_DIR){
- cprintf(" failed %s is a dir\n", name1);
iput(ip);
return -1;
}
@@ -583,12 +563,10 @@ link(char *name1, char *name2)
iunlock(ip);
if ((dp = namei(name2, NAMEI_CREATE, 0)) == 0) {
- cprintf(" failed %s exists\n", name2);
idecref(ip);
return -1;
}
if(dp->dev != ip->dev){
- cprintf(" cross-device link\n");
idecref(ip);
iput(dp);
return -1;
@@ -602,7 +580,5 @@ link(char *name1, char *name2)
iput(dp);
iput(ip);
- cprintf(" succeeded\n");
-
return 0;
}
diff --git a/init.c b/init.c
index 0a4223c..928371d 100644
--- a/init.c
+++ b/init.c
@@ -17,10 +17,7 @@ main(void)
open("console", 1);
open("console", 1);
- puts("init...\n");
-
while(1){
- puts("running sh...\n");
pid = fork();
if(pid == 0){
exec("sh", sh_args);
diff --git a/ioapic.c b/ioapic.c
index 0bd672a..5120b23 100644
--- a/ioapic.c
+++ b/ioapic.c
@@ -43,7 +43,6 @@ ioapic_init(void)
id = ioapic_read(io, IOAPIC_ID) >> APIC_ID_SHIFT;
if (id != ioapic_id)
panic ("ioapic_init: id isn't equal to ioapic_id\n");
- cprintf ("ioapic VER: 0x%x id %d nintr %d\n", l, id, nintr);
for (i = 0; i < nintr; i++) {
// active-hi and edge-triggered for ISA interrupts
// Assume that pin 0 on the first I/O APIC is an ExtINT pin.
@@ -78,5 +77,4 @@ ioapic_enable (int irq, int cpunum)
h &= ~IOART_DEST;
h |= (cpunum << APIC_ID_SHIFT);
ioapic_write(io, IOAPIC_REDTBL_HI(irq), h);
- cprintf("cpu%d: intr %d: lo 0x%x hi 0x%x\n", cpu(), irq, l, h);
}
diff --git a/picirq.c b/picirq.c
index 9fd7167..28b5e5d 100644
--- a/picirq.c
+++ b/picirq.c
@@ -22,13 +22,6 @@ irq_setmask_8259A(ushort mask)
outb(IO_PIC1+1, (char)mask);
outb(IO_PIC2+1, (char)(mask >> 8));
-
- cprintf("%d: enabled interrupts:", cpu());
-
- for (i = 0; i < 16; i++)
- if (~mask & (1<<i))
- cprintf(" %d", i);
- cprintf("\n");
}
/* Initialize the 8259A interrupt controllers. */
diff --git a/syscall.c b/syscall.c
index 71a7013..5cfc20b 100644
--- a/syscall.c
+++ b/syscall.c
@@ -284,7 +284,8 @@ sys_mknod(void)
return -1;
nip = mknod (cp->mem + arg0, (short) arg1, (short) arg2, (short) arg3);
- iput(nip);
+ if(nip)
+ iput(nip);
return (nip == 0) ? -1 : 0;
}
--
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