NeilBrown <neilb@suse.de>

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index e006c57bda54..adbac104f34c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -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: