2.4.22-rc1 FIFO bug still present

2.4.22-rc1 FIFO bug still present

[Rob van Nieuwkerk]

Hi Marcelo,

FYI:
I see that the "FIFO inode time-stamps are updated on a *readonly* fs"
bug is still not fixed in 2.4.22-rc1.

(this bug is a efficient way to destroy your CompactFlash devices in
certain applications ..)

Stephen C. Tweedie made a fix (see below) for it in May.
It has been in the Alan's -ac series since then and it works fine.

for more info see:

	http://www.ussg.iu.edu/hypermail/linux/kernel/0305.3/1132.html
	http://www.ussg.iu.edu/hypermail/linux/kernel/0305.3/1604.html

	greetings,
	Rob van Nieuwkerk

The patch:
(http://www.ussg.iu.edu/hypermail/linux/kernel/0305.3/att-1604/01-4202-vfs-mctime-rofs.patch):
###################################################################

--- linux-2.4-odirect/fs/inode.c.=K0001=.orig
+++ linux-2.4-odirect/fs/inode.c
@@ -1187,12 +1187,34 @@ void update_atime (struct inode *inode)
 {
 	if (inode->i_atime == CURRENT_TIME)
 		return;
-	if ( IS_NOATIME (inode) ) return;
-	if ( IS_NODIRATIME (inode) && S_ISDIR (inode->i_mode) ) return;
-	if ( IS_RDONLY (inode) ) return;
+	if (IS_NOATIME(inode))
+		return;
+	if (IS_NODIRATIME(inode) && S_ISDIR(inode->i_mode)) 
+		return;
+	if (IS_RDONLY(inode)) 
+		return;
 	inode->i_atime = CURRENT_TIME;
 	mark_inode_dirty_sync (inode);
-}   /*  End Function update_atime  */
+}
+
+/**
+ *	update_mctime	-	update the mtime and ctime
+ *	@inode: inode accessed
+ *
+ *	Update the modified and changed times on an inode for writes to special
+ *	files such as fifos.  No change is forced if the timestamps are already
+ *	up-to-date or if the filesystem is readonly.
+ */
+ 
+void update_mctime (struct inode *inode)
+{
+	if (inode->i_mtime == CURRENT_TIME && inode->i_ctime == CURRENT_TIME)
+		return;
+	if (IS_RDONLY(inode))
+		return;
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+	mark_inode_dirty (inode);
+}
 
 
 /*
--- linux-2.4-odirect/fs/pipe.c.=K0001=.orig
+++ linux-2.4-odirect/fs/pipe.c
@@ -230,8 +230,7 @@ pipe_write(struct file *filp, const char
 	/* Signal readers asynchronously that there is more data.  */
 	wake_up_interruptible(PIPE_WAIT(*inode));
 
-	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-	mark_inode_dirty(inode);
+	update_mctime(inode);
 
 out:
 	up(PIPE_SEM(*inode));
--- linux-2.4-odirect/include/linux/fs.h.=K0001=.orig
+++ linux-2.4-odirect/include/linux/fs.h
@@ -201,6 +201,7 @@ extern int leases_enable, dir_notify_ena
 #include <asm/byteorder.h>
 
 extern void update_atime (struct inode *);
+extern void update_mctime (struct inode *);
 #define UPDATE_ATIME(inode) update_atime (inode)
 
 extern void buffer_init(unsigned long);

Re: 2.4.22-rc1 FIFO bug still present

[Alan Cox]

On Mer, 2003-08-06 at 18:23, Rob van Nieuwkerk wrote:
> Stephen C. Tweedie made a fix (see below) for it in May.
> It has been in the Alan's -ac series since then and it works fine.

Certainly seems to be fine and it is a real bug. There is another unfixed
one of the same form with tty drivers too

Re: 2.4.22-rc1 FIFO bug still present

[Rob van Nieuwkerk]

On 08 Aug 2003 13:39:44 +0100
Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Mer, 2003-08-06 at 18:23, Rob van Nieuwkerk wrote:
> > Stephen C. Tweedie made a fix (see below) for it in May.
> > It has been in the Alan's -ac series since then and it works fine.
> 
> Certainly seems to be fine and it is a real bug. There is another unfixed
> one of the same form with tty drivers too

Hi Alan,

How does this other bug present itself ?
I use both console and serial port output in my readonly CF
application.  And I don't have any writes to the CF anymore after
fixing the FIFO bug.

	greetings,
	Rob van Nieuwkerk

Re: 2.4.22-rc1 FIFO bug still present

[Marcelo Tosatti]

On 8 Aug 2003, Alan Cox wrote:

> On Mer, 2003-08-06 at 18:23, Rob van Nieuwkerk wrote:
> > Stephen C. Tweedie made a fix (see below) for it in May.
> > It has been in the Alan's -ac series since then and it works fine.
> 
> Certainly seems to be fine and it is a real bug. There is another unfixed
> one of the same form with tty drivers too

Applied. 

Re: 2.4.22-rc1 FIFO bug still present

[Alan Cox]

On Gwe, 2003-08-08 at 13:54, Rob van Nieuwkerk wrote:
> How does this other bug present itself ?
> I use both console and serial port output in my readonly CF
> application.  And I don't have any writes to the CF anymore after
> fixing the FIFO bug.

create a tty device node
open it
delete it
mount the fs r/o or unmount it
close it

Re: 2.4.22-rc1 FIFO bug still present

[Bartlomiej Zolnierkiewicz]

Doh. It is not in 2.6-test too.

--bartlomiej