Re: 2.4.20-pre11 /proc/partitions read

[Christoph Hellwig <hch@infradead.org>]

On Tue, Oct 22, 2002 at 08:40:34PM +0200, Andries Brouwer wrote:
> On Tue, Oct 22, 2002 at 04:19:57PM +0200, Jan Kasprzak wrote:
> 
> > 	I.e. if you read the /proc/partitions in single read() call,
> > it gets read OK. However, if you read() with smaller-sized blocks,
> > you get the truncated contents.
> 
> Having statistics in /proc/partitions leads to such problems.
> Make sure you do not ask for them.

Andries,

have you actually CHECKED whether he has it enabled?

I rather suspect it's the following bug (introduce by me, but not
depend on CONFIG_BLK_STATS):

--- 1.23/drivers/block/genhd.c	Wed Aug 21 10:03:48 2002
+++ edited/drivers/block/genhd.c	Tue Oct 22 20:43:16 2002
@@ -155,13 +155,14 @@
 
 #ifdef CONFIG_PROC_FS
 /* iterator */
-static void *part_start(struct seq_file *s, loff_t *pos)
+static void *part_start(struct seq_file *s, loff_t *ppos)
 {
 	struct gendisk *gp;
+	loff_t pos = *ppos;
 
 	read_lock(&gendisk_lock);
 	for (gp = gendisk_head; gp; gp = gp->next)
-		if (!*pos--)
+		if (!pos--)
 			return gp;
 	return NULL;
 }