| Message ID | 1459371219-1815-2-git-send-email-luisbg@osg.samsung.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Mar 30, 2016 at 9:53 PM, Luis de Bethencourt <luisbg@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 <luisbg@osg.samsung.com> > Suggested-by: David Sterba <dsterba@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? > + /* 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On 30/03/16 22:48, Filipe Manana wrote: > On Wed, Mar 30, 2016 at 9:53 PM, Luis de Bethencourt > <luisbg@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 <luisbg@osg.samsung.com> >> Suggested-by: David Sterba <dsterba@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 >> >> -- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; + /* 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);
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 <luisbg@osg.samsung.com> Suggested-by: David Sterba <dsterba@suse.com> --- fs/btrfs/super.c | 5 +++++ 1 file changed, 5 insertions(+)