NeilBrown <neilb@suse.de>
akpm@linux-foundation.org [Mon, 16 Jul 2007 06:38:25 +0000 (23:38 -0700)]
The do_loop_readv_writev implementation of readv breaks out of the loop as
soon as a single read request didn't fill it's buffer:

if (nr != len)
break;

The generic_file_aio_read version doesn't.  So if it hits EOF before the end
of the list of buffers, it will try again on the next buffer.  If the file was
extended in the mean time, this will produce a bad result.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/filemap.c

index e006c57..adbac10 100644 (file)
@@ -1219,6 +1219,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                                retval = retval ?: desc.error;
                                break;
                        }
+                       if (desc.count > 0)
+                               break;
                }
        }
 out: