On Tue, Apr 30, 2019 at 12:09:32AM +0200, Andreas Gruenbacher wrote:
> In iomap_write_end, we're not holding a page reference anymore when
> calling the page_done callback, but the callback needs that reference to
> access the page. To fix that, move the put_page call in
> __generic_write_end into the callers of __generic_write_end. Then, in
> iomap_write_end, put the page after calling the page_done callback.
>
> Reported-by: Jan Kara <jack@xxxxxxx>
> Fixes: 63899c6f8851 ("iomap: add a page_done callback")
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> ---
> fs/buffer.c | 2 +-
> fs/iomap.c | 1 +
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/buffer.c b/fs/buffer.c
> index e0d4c6a5e2d2..0faa41fb4c88 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -2104,7 +2104,6 @@ void __generic_write_end(struct inode *inode, loff_t pos, unsigned copied,
> }
>
> unlock_page(page);
> - put_page(page);
>
> if (old_size < pos)
> pagecache_isize_extended(inode, old_size, pos);
> @@ -2160,6 +2159,7 @@ int generic_write_end(struct file *file, struct address_space *mapping,
> {
> copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
> __generic_write_end(mapping->host, pos, copied, page);
> + put_page(page);
> return copied;
> }
> EXPORT_SYMBOL(generic_write_end);
> diff --git a/fs/iomap.c b/fs/iomap.c
> index f8c9722d1a97..62e3461704ce 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -780,6 +780,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
> __generic_write_end(inode, pos, ret, page);
> if (iomap->page_done)
> iomap->page_done(inode, pos, copied, page, iomap);
> + put_page(page);
>
> if (ret < len)
> iomap_write_failed(inode, pos, len);
> --
> 2.20.1
>
