Adding upstream version 4.19.289.upstream/4.19.289

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 31 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 00dc1b5c8..34d56f0fa 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -5151,10 +5151,12 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
 	struct btrfs_key key;
+	struct btrfs_key orig_key;
 	struct btrfs_disk_key found_key;
 	int ret;
 
 	btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
+	orig_key = key;
 
 	if (key.offset > 0) {
 		key.offset--;
@@ -5171,8 +5173,36 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
 
 	btrfs_release_path(path);
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0)
+	if (ret <= 0)
 		return ret;
+
+	/*
+	 * Previous key not found. Even if we were at slot 0 of the leaf we had
+	 * before releasing the path and calling btrfs_search_slot(), we now may
+	 * be in a slot pointing to the same original key - this can happen if
+	 * after we released the path, one of more items were moved from a
+	 * sibling leaf into the front of the leaf we had due to an insertion
+	 * (see push_leaf_right()).
+	 * If we hit this case and our slot is > 0 and just decrement the slot
+	 * so that the caller does not process the same key again, which may or
+	 * may not break the caller, depending on its logic.
+	 */
+	if (path->slots[0] < btrfs_header_nritems(path->nodes[0])) {
+		btrfs_item_key(path->nodes[0], &found_key, path->slots[0]);
+		ret = comp_keys(&found_key, &orig_key);
+		if (ret == 0) {
+			if (path->slots[0] > 0) {
+				path->slots[0]--;
+				return 0;
+			}
+			/*
+			 * At slot 0, same key as before, it means orig_key is
+			 * the lowest, leftmost, key in the tree. We're done.
+			 */
+			return 1;
+		}
+	}
+
 	btrfs_item_key(path->nodes[0], &found_key, 0);
 	ret = comp_keys(&found_key, &key);
 	/*