linux-kernel - Re: [PATCH] loop: drop caches if offset or block

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Message-ID: <6742173c-170b-555e-edc2-f70314eccabf@kernel.dk>
Date:   Wed, 9 Jan 2019 20:51:59 -0700
From:   Jens Axboe <axboe@...nel.dk>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Cc:     linux-block@...r.kernel.org
Subject: Re: [PATCH] loop: drop caches if offset or block_size are changed

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