From 337c6f6830a5ceb650eaf10d38ed8e8f496c8f61 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 9 Jun 2014 13:22:13 +0100 Subject: [PATCH] Btrfs: ensure btrfs_prev_leaf doesn't miss 1 item We might have had an item with the previous key in the tree right before we released our path. And after we released our path, that item might have been pushed to the first slot (0) of the leaf we were holding due to a tree balance. Alternatively, an item with the previous key can exist as the only element of a leaf (big fat item). Therefore account for these 2 cases, so that our callers (like btrfs_previous_item) don't miss an existing item with a key matching the previous key we computed above. Signed-off-by: Filipe David Borba Manana Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index d99d9651dd58..4eada52f3969 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -5097,7 +5097,17 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) return ret; btrfs_item_key(path->nodes[0], &found_key, 0); ret = comp_keys(&found_key, &key); - if (ret < 0) + /* + * We might have had an item with the previous key in the tree right + * before we released our path. And after we released our path, that + * item might have been pushed to the first slot (0) of the leaf we + * were holding due to a tree balance. Alternatively, an item with the + * previous key can exist as the only element of a leaf (big fat item). + * Therefore account for these 2 cases, so that our callers (like + * btrfs_previous_item) don't miss an existing item with a key matching + * the previous key we computed above. + */ + if (ret <= 0) return 0; return 1; } -- GitLab