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Date: Thu, 30 Aug 2018 10:20:12 +0800 From: Chao Yu <yuchao0@...wei.com> To: Jaegeuk Kim <jaegeuk@...nel.org>, <linux-kernel@...r.kernel.org>, <linux-f2fs-devel@...ts.sourceforge.net> Subject: Re: [PATCH v2] f2fs: avoid wrong decrypted data from disk On 2018/8/30 9:48, 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@...nel.org> > --- > Change log from v1: > - move to bio != NULL > > fs/f2fs/data.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 382c1ef9a9e4..159e411785e9 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1556,6 +1556,12 @@ static int f2fs_mpage_readpages(struct address_space *mapping, > bio = NULL; > goto set_error_page; > } > + } else if (unlikely(f2fs_encrypted_file(inode))) { For android scenario, encryption becomes a common case now, so I think we can remove unlikely here. > + /* > + * If the page is under writeback, we need to wait for > + * its completion to see the correct decrypted data. > + */ > + f2fs_wait_on_block_writeback(F2FS_I_SB(inode), block_nr); > } Look at this again, it seems f2fs_wait_on_block_writeback() is not related to f2fs_grab_read_bio(), so we can move it here to make code logic more clear: if (f2fs_encrypted_file(inode)) { /* */ f2fs_wait_on_block_writeback(F2FS_I_SB(inode), block_nr); } Also, in f2fs_submit_page_read(), we need to adjust to: - f2fs_grab_read_bio() - f2fs_wait_on_block_writeback() - bio_add_page() How do you think? Thanks, > > if (bio_add_page(bio, page, blocksize, 0) < blocksize) >
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