diff mbox series

[6/7] btrfs: Promote to unsigned long long before shifting

Message ID 20201004180428.14494-7-willy@infradead.org
State New, archived
Headers show
Series Fix a pile of 4GB file problems on 32-bit | expand

Commit Message

Matthew Wilcox Oct. 4, 2020, 6:04 p.m. UTC
On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable@vger.kernel.org
Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/btrfs/raid56.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Josef Bacik Oct. 9, 2020, 2:18 p.m. UTC | #1
On 10/4/20 2:04 PM, Matthew Wilcox (Oracle) wrote:
> On 32-bit systems, this shift will overflow for files larger than 4GB.
> 
> Cc: stable@vger.kernel.org
> Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef
David Sterba Oct. 26, 2020, 4:35 p.m. UTC | #2
On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> On 32-bit systems, this shift will overflow for files larger than 4GB.
> 
> Cc: stable@vger.kernel.org
> Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  fs/btrfs/raid56.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> index 255490f42b5d..5ee0a53301bd 100644
> --- a/fs/btrfs/raid56.c
> +++ b/fs/btrfs/raid56.c
> @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
>  	u64 disk_start;
>  
>  	stripe = &rbio->bbio->stripes[stripe_nr];
> -	disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> +	disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);

It seems that this patch is mechanical replacement. If you check the
callers, the page_index is passed from an int that iterates over bits
set in an unsigned long (bitmap). The result won't overflow.
Matthew Wilcox Oct. 26, 2020, 4:44 p.m. UTC | #3
On Mon, Oct 26, 2020 at 05:35:46PM +0100, David Sterba wrote:
> On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> > On 32-bit systems, this shift will overflow for files larger than 4GB.
> > 
> > Cc: stable@vger.kernel.org
> > Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> >  fs/btrfs/raid56.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> > index 255490f42b5d..5ee0a53301bd 100644
> > --- a/fs/btrfs/raid56.c
> > +++ b/fs/btrfs/raid56.c
> > @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
> >  	u64 disk_start;
> >  
> >  	stripe = &rbio->bbio->stripes[stripe_nr];
> > -	disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> > +	disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
> 
> It seems that this patch is mechanical replacement. If you check the
> callers, the page_index is passed from an int that iterates over bits
> set in an unsigned long (bitmap). The result won't overflow.

Not mechanical, but I clearly made mistakes.  Will you pick up the
patches which actually fix bugs?
David Sterba Oct. 26, 2020, 5:03 p.m. UTC | #4
On Mon, Oct 26, 2020 at 04:44:42PM +0000, Matthew Wilcox wrote:
> On Mon, Oct 26, 2020 at 05:35:46PM +0100, David Sterba wrote:
> > On Sun, Oct 04, 2020 at 07:04:27PM +0100, Matthew Wilcox (Oracle) wrote:
> > > On 32-bit systems, this shift will overflow for files larger than 4GB.
> > > 
> > > Cc: stable@vger.kernel.org
> > > Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
> > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > > ---
> > >  fs/btrfs/raid56.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> > > index 255490f42b5d..5ee0a53301bd 100644
> > > --- a/fs/btrfs/raid56.c
> > > +++ b/fs/btrfs/raid56.c
> > > @@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
> > >  	u64 disk_start;
> > >  
> > >  	stripe = &rbio->bbio->stripes[stripe_nr];
> > > -	disk_start = stripe->physical + (page_index << PAGE_SHIFT);
> > > +	disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
> > 
> > It seems that this patch is mechanical replacement. If you check the
> > callers, the page_index is passed from an int that iterates over bits
> > set in an unsigned long (bitmap). The result won't overflow.
> 
> Not mechanical, but I clearly made mistakes.  Will you pick up the
> patches which actually fix bugs?

Yes, I just replied to the first patch, that does fix an overflow.
diff mbox series

Patch

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 255490f42b5d..5ee0a53301bd 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1089,7 +1089,7 @@  static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
 	u64 disk_start;
 
 	stripe = &rbio->bbio->stripes[stripe_nr];
-	disk_start = stripe->physical + (page_index << PAGE_SHIFT);
+	disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
 
 	/* if the device is missing, just fail this stripe */
 	if (!stripe->dev->bdev)