Commit cae79686 authored Aug 06, 2021 by Qu Wenruo Committed by David Sterba Oct 26, 2021

btrfs: defrag: also check PagePrivate for subpage cases in cluster_pages_for_defrag()



In function cluster_pages_for_defrag() we have a window where we unlock
page, either start the ordered range or read the content from disk.

When we re-lock the page, we need to make sure it still has the correct
page->private for subpage.

Thus add the extra PagePrivate check here to handle subpage cases
properly.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 1ccc2e8a

fs/btrfs/ioctl.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1278,7 +1278,8 @@ static int cluster_pages_for_defrag(struct inode *inode,
		* we unlocked the page above, so we need check if
		* it was released or not.
		*/
		if (page->mapping != inode->i_mapping) {
		if (page->mapping != inode->i_mapping \|\|
		!PagePrivate(page)) {
		unlock_page(page);
		put_page(page);
		goto again;
		@@ -1296,7 +1297,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
		}
		}

		if (page->mapping != inode->i_mapping) {
		if (page->mapping != inode->i_mapping \|\| !PagePrivate(page)) {
		unlock_page(page);
		put_page(page);
		goto again;