On Thu, Oct 20, 2016 at 01:35:42PM +0200, Jan Kara wrote: > iomap_page_mkwrite_actor() calls __block_write_begin_int() with position > masked as pos & ~PAGE_MASK which is equivalent to pos & (PAGE_SIZE-1). > Thus it masks off high bits of file position. However > __block_write_begin_int() expects full file position on input. This does > not cause any visible issues because all __block_write_begin_int() > really cares about are low file position bits but still it is a bug > waiting to happen. > > Signed-off-by: Jan Kara <jack@xxxxxxx> > --- > fs/iomap.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/fs/iomap.c b/fs/iomap.c > index 013d1d36fbbf..3341907eefc7 100644 > --- a/fs/iomap.c > +++ b/fs/iomap.c > @@ -433,8 +433,7 @@ iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, > struct page *page = data; > int ret; > > - ret = __block_write_begin_int(page, pos & ~PAGE_MASK, length, > - NULL, iomap); > + ret = __block_write_begin_int(page, pos, length, NULL, iomap); > if (ret) > return ret; Looks good. I've added it to my -rc3 fixes series. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
