Commit 0c9df7fb authored May 26, 2016 by Yunlong Song Committed by Jaegeuk Kim Jun 02, 2016

f2fs: return the errno to the caller to avoid using a wrong page

Commit aaf96075 ("f2fs: check node page
contents all the time") pointed out that "sometimes it was reported that
its contents was missing", so it checks the page's mapping and contents.
When "nid != nid_of_node(page)", ERR_PTR(-EIO) will be returned to the
caller. However, commit e1c51b9f ("f2fs:
clean up node page updating flow") moves "nid != nid_of_node(page)" test
to "f2fs_bug_on(sbi, nid != nid_of_node(page))", this will return a
wrong page to the caller when F2FS_CHECK_FS is off when "sometimes it
was reported that its contents was missing" happens.

This patch restores to check node page contents all the time, and
returns the errno to make the caller known something is wrong and avoid
to use the page. This patch also moves f2fs_bug_on to its proper location.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

parent 46ae957f

fs/f2fs/node.c

+10 −5

Original line number	Diff line number	Diff line
		@@ -1142,16 +1142,21 @@ repeat:

		lock_page(page);

		if (unlikely(!PageUptodate(page))) {
		f2fs_put_page(page, 1);
		return ERR_PTR(-EIO);
		}
		if (unlikely(!PageUptodate(page)))
		goto out_err;

		if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
		f2fs_put_page(page, 1);
		goto repeat;
		}
		page_hit:
		f2fs_bug_on(sbi, nid != nid_of_node(page));
		if(unlikely(nid != nid_of_node(page))) {
		f2fs_bug_on(sbi, 1);
		ClearPageUptodate(page);
		out_err:
		f2fs_put_page(page, 1);
		return ERR_PTR(-EIO);
		}
		return page;
		}

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