From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] loop: drop caches if offset or block_size are changed Date: Wed, 9 Jan 2019 20:51:59 -0700 Message-ID: <6742173c-170b-555e-edc2-f70314eccabf@kernel.dk> References: <20190110031714.39000-1-jaegeuk@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190110031714.39000-1-jaegeuk@kernel.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jaegeuk Kim , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: linux-block@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net On 1/9/19 8:17 PM, Jaegeuk Kim wrote: > If we don't drop caches used in old offset or block_size, we can get old data > from new offset/block_size, which gives unexpected data to user. > > For example, Martijn found a loopback bug in the below scenario. > 1) LOOP_SET_FD loads first two pages on loop file > 2) LOOP_SET_STATUS64 changes the offset on the loop file > 3) mount is failed due to the cached pages having wrong superblock Applied, thanks. -- Jens Axboe