From ef85b25e982b5bba1530b936e283ef129f02ab9d Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Fri, 2 Sep 2016 12:35:34 -0700 Subject: [PATCH] Btrfs: fix BUG_ON in btrfs_mark_buffer_dirty This can only happen with CONFIG_BTRFS_FS_CHECK_INTEGRITY=y. Commit 1ba98d0 ("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: 1ba98d086fe3 (Btrfs: detect corruption when non-root leaf has zero item) Cc: stable@vger.kernel.org # 4.8+ Reported-by: Jeff Mahoney Signed-off-by: Liu Bo Reviewed-by: Filipe Manana --- fs/btrfs/disk-io.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 3a57f99..c4e673a 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -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; } -- 2.7.4