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Date: Wed, 29 Aug 2018 21:03:31 -0700 From: Jaegeuk Kim <jaegeuk@...nel.org> To: Chao Yu <yuchao0@...wei.com> Cc: linux-kernel@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net Subject: Re: [PATCH v2] f2fs: avoid wrong decrypted data from disk On 08/30, Chao Yu wrote: > 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? Oh, yeah! > > Thanks, > > > > > if (bio_add_page(bio, page, blocksize, 0) < blocksize) > >
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