diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2020-03-04 11:18:24 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-01 13:17:45 +0200 |
| commit | c88596d593abaaa889c127fdd9fcc46f8178785f (patch) | |
| tree | 9a90307a89ac72630c29cc37aa7c31f803b8a052 /fs | |
| parent | 98c921e6be068a0759567eea5dbaaeabb0cdaee4 (diff) | |
btrfs: do not init a reloc root if we aren't relocating
[ Upstream commit 2abc726ab4b83db774e315c660ab8da21477092f ]
We previously were checking if the root had a dead root before accessing
root->reloc_root in order to avoid a use-after-free type bug. However
this scenario happens after we've unset the reloc control, so we would
have been saved if we'd simply checked for fs_info->reloc_control. At
this point during relocation we no longer need to be creating new reloc
roots, so simply move this check above the reloc_root checks to avoid
any future races and confusion.
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/relocation.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index af3605a0bf2e..1313506a7ecb 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1468,6 +1468,10 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, int clear_rsv = 0; int ret; + if (!rc || !rc->create_reloc_tree || + root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) + return 0; + /* * The subvolume has reloc tree but the swap is finished, no need to * create/update the dead reloc tree @@ -1481,10 +1485,6 @@ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, return 0; } - if (!rc || !rc->create_reloc_tree || - root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) - return 0; - if (!trans->reloc_reserved) { rsv = trans->block_rsv; trans->block_rsv = rc->block_rsv; @@ -2336,6 +2336,18 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, trans = NULL; goto out; } + + /* + * At this point we no longer have a reloc_control, so we can't + * depend on btrfs_init_reloc_root to update our last_trans. + * + * But that's ok, we started the trans handle on our + * corresponding fs_root, which means it's been added to the + * dirty list. At commit time we'll still call + * btrfs_update_reloc_root() and update our root item + * appropriately. + */ + reloc_root->last_trans = trans->transid; trans->block_rsv = rc->block_rsv; replaced = 0; |