Jeff Layton <jlayton@xxxxxxxxxx> writes:
> On Fri, 2022-04-01 at 12:38 +0100, Luís Henriques wrote:
>> When doing DIO on an encrypted node, we need to truncate the page cache in
>> the range being written to, otherwise the cache will include invalid data.
>>
>> Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
>> ---
>> fs/ceph/file.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> This patch should fix generic/647 fstest when run with test_dummy_encryption.
>>
>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>> index 5072570c2203..0f31c4d352a4 100644
>> --- a/fs/ceph/file.c
>> +++ b/fs/ceph/file.c
>> @@ -1895,6 +1895,11 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
>> req->r_inode = inode;
>> req->r_mtime = mtime;
>>
>> + if (IS_ENCRYPTED(inode) && (iocb->ki_flags & IOCB_DIRECT))
>> + truncate_inode_pages_range(
>> + inode->i_mapping, write_pos,
>> + PAGE_ALIGN(write_pos + write_len) - 1);
>> +
>> /* Set up the assertion */
>> if (rmw) {
>> /*
>
> Truncating the pagecache like this could cause dirty data to be
> discarded. I know we're planning to overwrite this range, but you are
> having to invalidate more than the written range here. We could
> potentially lose a write to that region.
>
> Have you tried using something like invalidate_inode_pages2_range ?
> That's more of what we'd want here, as it's a bit more cautious about
> tossing out dirty pages. I see too that that is what
> ceph_direct_read_write calls in the write case as well.
OK, let me try that instead. Yeah, I've used what the usual direct path
was using (the truncate_inode_pages_range()), but if
invalidate_inode_pages2_range works here I guess that's better. I'll test
that and send out v2.
Cheers,
--
Luís
