iomap: Don't create iomap_page objects for inline files

In iomap_readpage_actor, don't create iop objects for inline inodes.
Otherwise, iomap_read_inline_data will set PageUptodate without setting
iop->uptodate, and iomap_page_release will eventually complain.

To prevent this kind of bug from occurring in the future, make sure the
page doesn't have private data attached in iomap_read_inline_data.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

fs/iomap/buffered-io.c

@@ -215,6 +215,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
 	if (PageUptodate(page))
 		return;
 
+	BUG_ON(page_has_private(page));
 	BUG_ON(page->index);
 	BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
 
@@ -239,7 +240,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 {
 	struct iomap_readpage_ctx *ctx = data;
 	struct page *page = ctx->cur_page;
-	struct iomap_page *iop = iomap_page_create(inode, page);
+	struct iomap_page *iop;
 	bool same_page = false, is_contig = false;
 	loff_t orig_pos = pos;
 	unsigned poff, plen;
@@ -252,6 +253,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	}
 
 	/* zero post-eof blocks as the page may be mapped */
+	iop = iomap_page_create(inode, page);
 	iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
 	if (plen == 0)
 		goto done;