From: Filipe Manana fdmanana@suse.com
commit c7967fc1499beb9b70bb9d33525fb0b384af8883 upstream.
If we fail to reserve metadata for delalloc operations we end up releasing the previously reserved qgroup amount twice, once explicitly under the 'out_qgroup' label by calling btrfs_qgroup_free_meta_prealloc() and once again, under label 'out_fail', by calling btrfs_inode_rsv_release() with a value of 'true' for its 'qgroup_free' argument, which results in btrfs_qgroup_free_meta_prealloc() being called again, so we end up having a double free.
Also if we fail to reserve the necessary qgroup amount, we jump to the label 'out_fail', which calls btrfs_inode_rsv_release() and that in turns calls btrfs_qgroup_free_meta_prealloc(), even though we weren't able to reserve any qgroup amount. So we freed some amount we never reserved.
So fix this by removing the call to btrfs_inode_rsv_release() in the failure path, since it's not necessary at all as we haven't changed the inode's block reserve in any way at this point.
Fixes: c8eaeac7b73434 ("btrfs: reserve delalloc metadata differently") CC: stable@vger.kernel.org # 5.2+ Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/delalloc-space.c | 1 - 1 file changed, 1 deletion(-)
--- a/fs/btrfs/delalloc-space.c +++ b/fs/btrfs/delalloc-space.c @@ -371,7 +371,6 @@ int btrfs_delalloc_reserve_metadata(stru out_qgroup: btrfs_qgroup_free_meta_prealloc(root, qgroup_reserve); out_fail: - btrfs_inode_rsv_release(inode, true); if (delalloc_lock) mutex_unlock(&inode->delalloc_mutex); return ret;