Commit ef85b25e authored Sep 02, 2016 by Liu Bo Committed by Filipe Manana Nov 23, 2016

Btrfs: fix BUG_ON in btrfs_mark_buffer_dirty



This can only happen with CONFIG_BTRFS_FS_CHECK_INTEGRITY=y.

Commit 1ba98d08 ("Btrfs: detect corruption when non-root leaf has zero item")
assumes that a leaf is its root when leaf->bytenr == btrfs_root_bytenr(root),
however, we should not use btrfs_root_bytenr(root) since it's mainly got
updated during committing transaction.  So the check can fail when doing
COW on this leaf while it is a root.

This changes to use "if (leaf == btrfs_root_node(root))" instead, just like
how we check whether leaf is a root in __btrfs_cow_block().

Fixes: 1ba98d08 (Btrfs: detect corruption when non-root leaf has zero item)
Cc: stable@vger.kernel.org  # 4.8+
Reported-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

parent 2a2a83de

fs/btrfs/disk-io.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -572,13 +572,17 @@ static noinline int check_leaf(struct btrfs_root *root,
		* open_ctree() some roots has not yet been set up.
		*/
		if (!IS_ERR_OR_NULL(check_root)) {
		struct extent_buffer *eb;

		eb = btrfs_root_node(check_root);
		/* if leaf is the root, then it's fine */
		if (leaf->start !=
		btrfs_root_bytenr(&check_root->root_item)) {
		if (leaf != eb) {
		CORRUPT("non-root leaf's nritems is 0",
		leaf, root, 0);
		leaf, check_root, 0);
		free_extent_buffer(eb);
		return -EIO;
		}
		free_extent_buffer(eb);
		}
		return 0;
		}