From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:46542 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388125AbeGWPN4 (ORCPT ); Mon, 23 Jul 2018 11:13:56 -0400 Subject: Re: [PATCH 5/7] btrfs: warn for num_devices below 0 To: dsterba@suse.cz, linux-btrfs@vger.kernel.org References: <20180716145812.20836-1-anand.jain@oracle.com> <20180716145812.20836-6-anand.jain@oracle.com> <20180723140103.GN26141@twin.jikos.cz> From: Anand Jain Message-ID: <535b5ee9-b935-6d5d-b7b0-20a46b07b10c@oracle.com> Date: Mon, 23 Jul 2018 22:15:52 +0800 MIME-Version: 1.0 In-Reply-To: <20180723140103.GN26141@twin.jikos.cz> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 07/23/2018 10:01 PM, David Sterba wrote: > On Mon, Jul 16, 2018 at 10:58:10PM +0800, Anand Jain wrote: >> In preparation to de-duplicate a section of code where we deduce the >> num_devices, use warn instead of bug. >> >> Signed-off-by: Anand Jain >> --- >> fs/btrfs/volumes.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index 7f4973fc2b52..0f4c512aa6b4 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -3726,7 +3726,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info, >> num_devices = fs_info->fs_devices->num_devices; >> btrfs_dev_replace_read_lock(&fs_info->dev_replace); >> if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) { >> - BUG_ON(num_devices < 1); >> + WARN_ON(num_devices < 1); > > I wonder if there any valid cases when there are 0 devices when balance > is started, ie. before num_devices gets decremented. num_devices counts the in-memory devices of a fsid. On a mounted FS num_devices > 0 always. > The WARN_ON is either redundant or should be turned to a proper sanity > check. Yes is redundant. I suggest to delete it. Thanks, Anand >> num_devices--; > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >