[PATCH] 2.6.6 buffer.c: bio_alloc() check

[PATCH] 2.6.6 buffer.c: bio_alloc() check

[Yury Umanets]

[PATCH] 2.6.6 buffer.c: adds bio_alloc() check and error handling in
fs/buffer.c.

Signed-off-by: Yury Umanets <torque@ukrpost.net>

 buffer.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+)

diff -rupN ./linux-2.6.6/fs/buffer.c ./linux-2.6.6-modified/fs/buffer.c
--- ./linux-2.6.6/fs/buffer.c	Mon May 10 05:32:38 2004
+++ ./linux-2.6.6-modified/fs/buffer.c	Wed Jun  2 15:21:47 2004
@@ -2712,6 +2712,31 @@ void submit_bh(int rw, struct buffer_hea
 	 * submit_bio -> generic_make_request may further map this bio around
 	 */
 	bio = bio_alloc(GFP_NOIO, 1);
+	if (bio == NULL) {
+		char b[BDEVNAME_SIZE];
+                
+		printk(KERN_ERR "BIO allocation failed for buffer on device "
+			"%s, logical block %Lu\n", bdevname(bh->b_bdev, b), 
+			(unsigned long long)bh->b_blocknr);
+                
+		/* 
+		 * this is needed here as some of submit_bh() callers have to
+		 * wait until buffer is unlocked (that is IO is finished on it)
+		 * and check its state.
+		 */
+		if (rw == WRITE)
+			set_buffer_write_io_error(bh);
+		clear_buffer_uptodate(bh);
+		SetPageError(bh->b_page);
+                
+		/* 
+		 * making all future wait_on_buffer() callers do not wait
+		 * this buffer as it is errorneous. 
+		 */
+		if (buffer_locked(bh))
+			unlock_buffer(bh);
+		return;
+        }
 
 	bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
 	bio->bi_bdev = bh->b_bdev;


-- 
umka

Re: [PATCH] 2.6.6 buffer.c: bio_alloc() check

[Jens Axboe]

On Wed, Jun 02 2004, Yury Umanets wrote:
> [PATCH] 2.6.6 buffer.c: adds bio_alloc() check and error handling in
> fs/buffer.c.
> 
> Signed-off-by: Yury Umanets <torque@ukrpost.net>
> 
>  buffer.c |   25 +++++++++++++++++++++++++
>  1 files changed, 25 insertions(+)
> 
> diff -rupN ./linux-2.6.6/fs/buffer.c ./linux-2.6.6-modified/fs/buffer.c
> --- ./linux-2.6.6/fs/buffer.c	Mon May 10 05:32:38 2004
> +++ ./linux-2.6.6-modified/fs/buffer.c	Wed Jun  2 15:21:47 2004
> @@ -2712,6 +2712,31 @@ void submit_bh(int rw, struct buffer_hea
>  	 * submit_bio -> generic_make_request may further map this bio around
>  	 */
>  	bio = bio_alloc(GFP_NOIO, 1);
> +	if (bio == NULL) {

This is wrong, bio_alloc() never fails if it's called with __GFP_WAIT in
the gfp mask.

-- 
Jens Axboe

Re: [PATCH] 2.6.6 buffer.c: bio_alloc() check

[Yury Umanets]

On Wed, 2004-06-02 at 16:36, Jens Axboe wrote:
> On Wed, Jun 02 2004, Yury Umanets wrote:
> > [PATCH] 2.6.6 buffer.c: adds bio_alloc() check and error handling in
> > fs/buffer.c.
> > 
> > Signed-off-by: Yury Umanets <torque@ukrpost.net>
> > 
> >  buffer.c |   25 +++++++++++++++++++++++++
> >  1 files changed, 25 insertions(+)
> > 
> > diff -rupN ./linux-2.6.6/fs/buffer.c ./linux-2.6.6-modified/fs/buffer.c
> > --- ./linux-2.6.6/fs/buffer.c	Mon May 10 05:32:38 2004
> > +++ ./linux-2.6.6-modified/fs/buffer.c	Wed Jun  2 15:21:47 2004
> > @@ -2712,6 +2712,31 @@ void submit_bh(int rw, struct buffer_hea
> >  	 * submit_bio -> generic_make_request may further map this bio around
> >  	 */
> >  	bio = bio_alloc(GFP_NOIO, 1);
> > +	if (bio == NULL) {
> 
> This is wrong, bio_alloc() never fails if it's called with __GFP_WAIT in
> the gfp mask.
Ok, I see. Thanks.

-- 
umka