Re: [PATCH] f2fs: avoid wrong decrypted data from disk

From: Chao Yu
Date: Tue Aug 28 2018 - 22:14:38 EST


On 2018/8/28 6:52, Jaegeuk Kim wrote:
> 1. Create a file in an encrypted directory
> 2. Do GC & drop caches
> 3. Read stale data before its bio for metapage was not issued yet
>
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
> ---
> fs/f2fs/data.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 382c1ef9a9e4..c3557fd4a0bd 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1550,6 +1550,13 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
> bio = NULL;
> }
> if (bio == NULL) {
> + /*
> + * If the page is under writeback, we need to wait for
> + * its completion to see the correct decrypted data.
> + */
> + if (unlikely(f2fs_encrypted_file(inode)))
> + f2fs_wait_on_block_writeback(F2FS_I_SB(inode), block_nr);

I think we have did this in f2fs_grab_read_bio(), so we just need to cover 'bio
!= NULL' case, right?

Thanks,

> +
> bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
> is_readahead ? REQ_RAHEAD : 0);
> if (IS_ERR(bio)) {
>