From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out5-smtp.messagingengine.com ([66.111.4.29]:51143 "EHLO out5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932833AbcA0RRx (ORCPT ); Wed, 27 Jan 2016 12:17:53 -0500 Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id B42D032ACA for ; Wed, 27 Jan 2016 12:17:52 -0500 (EST) Subject: FAILED: patch "[PATCH] direct-io: Fix negative return from dio read beyond eof" failed to apply to 3.14-stable tree To: jack@suse.cz, avi@scylladb.com, axboe@fb.com, swhiteho@redhat.com Cc: From: Date: Wed, 27 Jan 2016 09:17:51 -0800 Message-ID: <145391507133102@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 3.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 74cedf9b6c603f2278a05bc91b140b32b434d0b5 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 30 Nov 2015 10:15:42 -0700 Subject: [PATCH] direct-io: Fix negative return from dio read beyond eof Assume a filesystem with 4KB blocks. When a file has size 1000 bytes and we issue direct IO read at offset 1024, blockdev_direct_IO() reads the tail of the last block and the logic for handling short DIO reads in dio_complete() results in a return value -24 (1000 - 1024) which obviously confuses userspace. Fix the problem by bailing out early once we sample i_size and can reliably check that direct IO read starts beyond i_size. Reported-by: Avi Kivity Fixes: 9fe55eea7e4b444bafc42fa0000cc2d1d2847275 CC: stable@vger.kernel.org CC: Steven Whitehouse Signed-off-by: Jan Kara Signed-off-by: Jens Axboe diff --git a/fs/direct-io.c b/fs/direct-io.c index cb5337d8c273..1c75a3a07f8f 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1169,6 +1169,15 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, } } + /* Once we sampled i_size check for reads beyond EOF */ + dio->i_size = i_size_read(inode); + if (iov_iter_rw(iter) == READ && offset >= dio->i_size) { + if (dio->flags & DIO_LOCKING) + mutex_unlock(&inode->i_mutex); + kmem_cache_free(dio_cache, dio); + goto out; + } + /* * For file extending writes updating i_size before data writeouts * complete can expose uninitialized blocks in dumb filesystems. @@ -1222,7 +1231,6 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, sdio.next_block_for_io = -1; dio->iocb = iocb; - dio->i_size = i_size_read(inode); spin_lock_init(&dio->bio_lock); dio->refcount = 1;