On Sat 02-11-19 16:13:03, Konstantin Khlebnikov wrote:
> Function generic_file_direct_write() tries to invalidate pagecache after
> O_DIRECT write. Unlike to similar code in dio_complete() this silently
> ignores error returned from invalidate_inode_pages2_range().
>
> According to comment this code here because not all filesystems call
> dio_complete() to do proper invalidation after O_DIRECT write.
> Noticeable example is a blkdev_direct_IO().
>
> This patch calls dio_warn_stale_pagecache() if invalidation fails.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> mm/filemap.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 189b8f318da2..dc3b78db079b 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -3241,11 +3241,13 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
> * do not end up with dio_complete() being called, so let's not break
> * them by removing it completely.
> *
> + * Noticeable example is a blkdev_direct_IO().
> + *
> * Skip invalidation for async writes or if mapping has no pages.
> */
> - if (written > 0 && mapping->nrpages)
> - invalidate_inode_pages2_range(mapping,
> - pos >> PAGE_SHIFT, end);
> + if (written > 0 && mapping->nrpages &&
> + invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, end))
> + dio_warn_stale_pagecache(file);
>
> if (written > 0) {
> pos += written;
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
