Re: [PATCH v3] ceph: invalidate pages when doing direct/sync writes

[Jeff Layton]

On Thu, 2022-04-07 at 15:38 +0100, Luís Henriques wrote:
> When doing a direct/sync write, we need to invalidate the page cache in
> the range being written to.  If we don't do this, the cache will include
> invalid data as we just did a write that avoided the page cache.
> 
> Signed-off-by: Luís Henriques <lhenriques@xxxxxxx>
> ---
>  fs/ceph/file.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> Ok, here's a new attempt.  After discussion in this thread and on IRC, I
> think this is the right fix.  generic/647 now passes with and without
> encryption.  Thanks!
> 
> Changes since v2:
> - Invalidation needs to be done after a write
> 
> 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
> 
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 5072570c2203..63e67eb60310 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1938,6 +1938,15 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
>  			break;
>  		}
>  		ceph_clear_error_write(ci);
> +		ret = invalidate_inode_pages2_range(
> +				inode->i_mapping,
> +				pos >> PAGE_SHIFT,
> +				(pos + len - 1) >> PAGE_SHIFT);
> +		if (ret < 0) {
> +			dout("invalidate_inode_pages2_range returned %d\n",
> +			     ret);
> +			ret = 0;
> +		}
>  		pos += len;
>  		written += len;
>  		dout("sync_write written %d\n", written);

Looks good. I suspect we can also remove the
invalidate_indode_pages2_range call earlier in this function too. I may
roll that into this patch.

I'll give this an xfstests run with fscrypt enabled and see how it does.

Thanks!
-- 
Jeff Layton <jlayton@xxxxxxxxxx>