From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 936F221D49185 for ; Wed, 15 May 2019 12:27:34 -0700 (PDT) From: Vivek Goyal Subject: [PATCH v2 29/30] fuse: Take inode lock for dax inode truncation Date: Wed, 15 May 2019 15:27:14 -0400 Message-Id: <20190515192715.18000-30-vgoyal@redhat.com> In-Reply-To: <20190515192715.18000-1-vgoyal@redhat.com> References: <20190515192715.18000-1-vgoyal@redhat.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-nvdimm@lists.01.org Cc: swhiteho@redhat.com, dgilbert@redhat.com, stefanha@redhat.com, miklos@szeredi.hu List-ID: When a file is opened with O_TRUNC, we need to make sure that any other DAX operation is not in progress. DAX expects i_size to be stable. In fuse_iomap_begin() we check for i_size at multiple places and we expect i_size to not change. Another problem is, if we setup a mapping in fuse_iomap_begin(), and file gets truncated and dax read/write happens, KVM currently hangs. It tries to fault in a page which does not exist on host (file got truncated). It probably requries fixing in KVM. So for now, take inode lock. Once KVM is fixed, we might have to have a look at it again. Signed-off-by: Vivek Goyal --- fs/fuse/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 9b82d9b4ebc3..d0979dc32f08 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -420,7 +420,7 @@ int fuse_open_common(struct inode *inode, struct file *file, bool isdir) int err; bool lock_inode = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc && - fc->writeback_cache; + (fc->writeback_cache || IS_DAX(inode)); err = generic_file_open(inode, file); if (err) -- 2.20.1 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm