Re: minix fs corruption fix for 2.4

[Linus Torvalds]

On Mon, 3 Nov 2003, Konstantin Boldyshev wrote:
> 
> Enclosed is a simple patch to fix corruption of minix filesystem
> when deleting character and block device nodes (special files).
> From what I've found out the bug was introduced somehwere in 2.3
> and is present in all 2.4 versions, and I guess also goes into 2.6.

Oops, yes.

The problem is that block and character devices put not a block number but 
a _device_ number in the place where other files put their block 
allocations.

Your patch is wrong, though - you shouldn't test for APPEND and IMMUTABLE 
here. That should be done at higher layers. 

I'd also prefer to do the test the other way around: test for CHRDEV and 
BLKDEV in inode.c the same way the other functions do. Something like the 
appended..

Al, can you verify? I think this crept in when you did the block lookup 
cleanups. I also worry whether anybody else got the bug?

		Linus

===== fs/minix/inode.c 1.38 vs edited =====
--- 1.38/fs/minix/inode.c	Fri Sep  5 04:31:53 2003
+++ edited/fs/minix/inode.c	Mon Nov  3 08:51:01 2003
@@ -547,6 +547,8 @@
  */
 void minix_truncate(struct inode * inode)
 {
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+		return;
 	if (INODE_VERSION(inode) == MINIX_V1)
 		V1_minix_truncate(inode);
 	else

-
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