tree 9bff9e2a4f1e0346fff5ed17d60ef503d555eeef
parent f28de8d8fd376ba57aaed53cdc1a0ba2238e8ebf
author Josef Bacik <josef@toxicpanda.com> 1584114287 -0400
committer David Sterba <dsterba@suse.com> 1584979318 +0100

btrfs: hold a ref on the root->reloc_root

We previously were relying on root->reloc_root to be cleaned up by the
drop snapshot, or the error handling.  However if btrfs_drop_snapshot()
failed it wouldn't drop the ref for the root.  Also we sort of depend on
the right thing to happen with moving reloc roots between lists and the
fs root they belong to, which makes it hard to figure out who owns the
reference.

Fix this by explicitly holding a reference on the reloc root for
roo->reloc_root.  This means that we hold two references on reloc roots,
one for whichever reloc_roots list it's attached to, and the
root->reloc_root we're on.

This makes it easier to reason out who owns a reference on the root, and
when it needs to be dropped.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>