On Mon 24-04-17 19:41:32, Andrey Ryabinin wrote:
> Some direct IO write fs hooks call invalidate_inode_pages2[_range]()
> conditionally iff mapping->nrpages is not zero. This can't be right,
> because invalidate_inode_pages2[_ragne]() also invalidate data in
> the cleancache via cleancache_invalidate_inode() call.
> So if page cache is empty but there is some data in the cleancache,
> buffered read after direct IO write would get stale data from
> the cleancache.
>
> Also it doesn't feel right to check only for ->nrpages because
> invalidate_inode_pages2[_range] invalidates exceptional entries as well.
>
> Fix this by calling invalidate_inode_pages2[_range]() regardless of nrpages
> state.
>
> Note: nfs,cifs,9p doesn't need similar fix because the never call
> cleancache_get_page() (nor directly, nor via mpage_readpage[s]()), so they
> are not affected by this bug.
>
> Fixes: c515e1fd361c ("mm/fs: add hooks to support cleancache")
> Signed-off-by: Andrey Ryabinin <[email protected]>
> Acked-by: Konrad Rzeszutek Wilk <[email protected]>
> Cc: <[email protected]>
OK, looks good. You can add:
Reviewed-by: Jan Kara <[email protected]>
Honza
> ---
> fs/iomap.c | 18 ++++++++----------
> mm/filemap.c | 26 +++++++++++---------------
> 2 files changed, 19 insertions(+), 25 deletions(-)
>
> diff --git a/fs/iomap.c b/fs/iomap.c
> index cdeed39..f6a6013 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -881,16 +881,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> flags |= IOMAP_WRITE;
> }
>
> - if (mapping->nrpages) {
> - ret = filemap_write_and_wait_range(mapping, start, end);
> - if (ret)
> - goto out_free_dio;
> + ret = filemap_write_and_wait_range(mapping, start, end);
> + if (ret)
> + goto out_free_dio;
>
> - ret = invalidate_inode_pages2_range(mapping,
> - start >> PAGE_SHIFT, end >> PAGE_SHIFT);
> - WARN_ON_ONCE(ret);
> - ret = 0;
> - }
> + ret = invalidate_inode_pages2_range(mapping,
> + start >> PAGE_SHIFT, end >> PAGE_SHIFT);
> + WARN_ON_ONCE(ret);
> + ret = 0;
>
> inode_dio_begin(inode);
>
> @@ -945,7 +943,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> * one is a pretty crazy thing to do, so we don't support it 100%. If
> * this invalidation fails, tough, the write still worked...
> */
> - if (iov_iter_rw(iter) == WRITE && mapping->nrpages) {
> + if (iov_iter_rw(iter) == WRITE) {
> int err = invalidate_inode_pages2_range(mapping,
> start >> PAGE_SHIFT, end >> PAGE_SHIFT);
> WARN_ON_ONCE(err);
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 9eab40e..b7b973b 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2720,18 +2720,16 @@ generic_file_direct_write(struct kiocb *iocb, struct
> iov_iter *from)
> * about to write. We do this *before* the write so that we can return
> * without clobbering -EIOCBQUEUED from ->direct_IO().
> */
> - if (mapping->nrpages) {
> - written = invalidate_inode_pages2_range(mapping,
> + written = invalidate_inode_pages2_range(mapping,
> pos >> PAGE_SHIFT, end);
> - /*
> - * If a page can not be invalidated, return 0 to fall back
> - * to buffered write.
> - */
> - if (written) {
> - if (written == -EBUSY)
> - return 0;
> - goto out;
> - }
> + /*
> + * If a page can not be invalidated, return 0 to fall back
> + * to buffered write.
> + */
> + if (written) {
> + if (written == -EBUSY)
> + return 0;
> + goto out;
> }
>
> written = mapping->a_ops->direct_IO(iocb, from);
> @@ -2744,10 +2742,8 @@ generic_file_direct_write(struct kiocb *iocb, struct
> iov_iter *from)
> * so we don't support it 100%. If this invalidation
> * fails, tough, the write still worked...
> */
> - if (mapping->nrpages) {
> - invalidate_inode_pages2_range(mapping,
> - pos >> PAGE_SHIFT, end);
> - }
> + invalidate_inode_pages2_range(mapping,
> + pos >> PAGE_SHIFT, end);
>
> if (written > 0) {
> pos += written;
> --
> 2.10.2
>
--
Jan Kara <[email protected]>
SUSE Labs, CR
