From: Josef Bacik Date: Fri, 13 Mar 2020 21:17:06 +0000 (-0400) Subject: btrfs: reloc: reorder reservation before root selection X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5f6b2e5cd67a7bb39eb24fa3206e54803e1a25ff;p=linux.git btrfs: reloc: reorder reservation before root selection Since we're not only checking for metadata reservations but also if we need to throttle our delayed ref generation, reorder reserve_metadata_space() above the select_one_root() call in relocate_tree_block(). The reason we want this is because select_reloc_root() will mess with the backref cache, and if we're going to bail we want to be able to cleanly remove this node from the backref cache and come back along to regenerate it. Move it up so this is the first thing we do to make restarting cleaner. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 63b11e546a875..73d9dc192fbb5 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3177,6 +3177,14 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, if (!node) return 0; + /* + * If we fail here we want to drop our backref_node because we are going + * to start over and regenerate the tree for it. + */ + ret = reserve_metadata_space(trans, rc, node); + if (ret) + goto out; + BUG_ON(node->processed); root = select_one_root(node); if (root == ERR_PTR(-ENOENT)) { @@ -3184,12 +3192,6 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans, goto out; } - if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { - ret = reserve_metadata_space(trans, rc, node); - if (ret) - goto out; - } - if (root) { if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { BUG_ON(node->new_bytenr);