From: Xiubo Li <xiubli@redhat.com>
To: "Luís Henriques" <lhenriques@suse.de>
Cc: Jeff Layton <jlayton@kernel.org>,
Ilya Dryomov <idryomov@gmail.com>,
ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ceph: invalidate pages when doing DIO in encrypted inodes
Date: Wed, 6 Apr 2022 19:18:04 +0800 [thread overview]
Message-ID: <6ba91390-83e8-8702-2729-dc432abd3cc5@redhat.com> (raw)
In-Reply-To: <878rsia391.fsf@brahms.olymp>
On 4/6/22 6:57 PM, Luís Henriques wrote:
> Xiubo Li <xiubli@redhat.com> writes:
>
>> On 4/1/22 9:32 PM, Luís Henriques wrote:
>>> When doing DIO on an encrypted node, we need to invalidate the page cache in
>>> the range being written to, otherwise the cache will include invalid data.
>>>
>>> Signed-off-by: Luís Henriques <lhenriques@suse.de>
>>> ---
>>> fs/ceph/file.c | 11 ++++++++++-
>>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>>
>>> Changes since v1:
>>> - Replaced truncate_inode_pages_range() by invalidate_inode_pages2_range
>>> - Call fscache_invalidate with FSCACHE_INVAL_DIO_WRITE if we're doing DIO
>>>
>>> Note: I'm not really sure this last change is required, it doesn't really
>>> affect generic/647 result, but seems to be the most correct.
>>>
>>> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
>>> index 5072570c2203..b2743c342305 100644
>>> --- a/fs/ceph/file.c
>>> +++ b/fs/ceph/file.c
>>> @@ -1605,7 +1605,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
>>> if (ret < 0)
>>> return ret;
>>> - ceph_fscache_invalidate(inode, false);
>>> + ceph_fscache_invalidate(inode, (iocb->ki_flags & IOCB_DIRECT));
>>> ret = invalidate_inode_pages2_range(inode->i_mapping,
>>> pos >> PAGE_SHIFT,
>>> (pos + count - 1) >> PAGE_SHIFT);
>> The above has already invalidated the pages, why doesn't it work ?
> I suspect the reason is because later on we loop through the number of
> pages, call copy_page_from_iter() and then ceph_fscrypt_encrypt_pages().
Checked the 'copy_page_from_iter()', it will do the kmap for the pages
but will kunmap them again later. And they shouldn't update the
i_mapping if I didn't miss something important.
For 'ceph_fscrypt_encrypt_pages()' it will encrypt/dencrypt the context
inplace, IMO if it needs to map the page and it should also unmap it
just like in 'copy_page_from_iter()'.
I thought it possibly be when we need to do RMW, it may will update the
i_mapping when reading contents, but I checked the code didn't find any
place is doing this. So I am wondering where tha page caches come from ?
If that page caches really from reading the contents, then we should
discard it instead of flushing it back ?
BTW, what's the problem without this fixing ? xfstest fails ?
-- Xiubo
> Cheers,
next prev parent reply other threads:[~2022-04-06 13:48 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 13:32 [PATCH v2] ceph: invalidate pages when doing DIO in encrypted inodes Luís Henriques
2022-04-06 5:24 ` Xiubo Li
2022-04-06 10:50 ` Luís Henriques
2022-04-06 10:57 ` Xiubo Li
2022-04-06 6:28 ` Xiubo Li
2022-04-06 10:57 ` Luís Henriques
2022-04-06 11:18 ` Xiubo Li [this message]
2022-04-06 11:33 ` Luís Henriques
2022-04-06 11:48 ` Jeff Layton
2022-04-06 13:10 ` Xiubo Li
2022-04-06 13:41 ` Jeff Layton
2022-04-07 1:17 ` Xiubo Li
2022-04-07 11:55 ` Luís Henriques
2022-04-07 13:23 ` Jeff Layton
2022-04-07 14:08 ` Jeff Layton
2022-04-07 3:19 ` Xiubo Li
2022-04-07 9:06 ` Luís Henriques
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