On 30/03/16 22:48, Filipe Manana wrote: > On Wed, Mar 30, 2016 at 9:53 PM, Luis de Bethencourt > <lui...@osg.samsung.com> wrote: >> Since mixed block groups accounting isn't byte-accurate and f_bree is an >> unsigned integer, it could overflow. Avoid this. >> >> Signed-off-by: Luis de Bethencourt <lui...@osg.samsung.com> >> Suggested-by: David Sterba <dste...@suse.com> >> --- >> fs/btrfs/super.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c >> index bdca79c..93376d0 100644 >> --- a/fs/btrfs/super.c >> +++ b/fs/btrfs/super.c >> @@ -2101,6 +2101,11 @@ static int btrfs_statfs(struct dentry *dentry, struct >> kstatfs *buf) >> /* Account global block reserve as used, it's in logical size >> already */ >> spin_lock(&block_rsv->lock); >> buf->f_bfree -= block_rsv->size >> bits; > > You forgot to remove the line above, didn't you? >
Shoot! Indeed I did, sorry. Thanks for noticing. Sending version 2. Luis >> + /* Mixed block groups accounting is not byte-accurate, avoid >> overflow */ >> + if (buf->f_bfree >= block_rsv->size >> bits) >> + buf->f_bfree -= block_rsv->size >> bits; >> + else >> + buf->f_bfree = 0; >> spin_unlock(&block_rsv->lock); >> >> buf->f_bavail = div_u64(total_free_data, factor); >> -- >> 2.5.3 >> >> --
