Re: [PATCH v3] btrfs: fix a check-integrity warning on write caching disabled disk

[Wang Yugui <wangyugui@e16-tech.com>]

Hi,

> On Wed, Nov 03, 2021 at 08:07:22AM +0800, Wang Yugui wrote:
> > Hi,
> > 
> > > On Thu, Oct 28, 2021 at 06:32:54AM +0800, Wang Yugui wrote:
> > > > When a disk has write caching disabled, we skip submission of a bio
> > > > with flush and sync requests before writing the superblock, since
> > > > it's not needed. However when the integrity checker is enabled,
> > > > this results in reports that there are metadata blocks referred
> > > > by a superblock that were not properly flushed. So don't skip the
> > > > bio submission only when the integrity checker is enabled
> > > > for the sake of simplicity, since this is a debug tool and
> > > > not meant for use in non-debug builds.
> > > > 
> > > > xfstest/btrfs/220 trigger a check-integrity warning like the following
> > > > when CONFIG_BTRFS_FS_CHECK_INTEGRITY=y and the disk with WCE=0.
> > > 
> > > Does this need the integrity checker to be also enabled by mount
> > > options? I don't think compile time (ie the #ifdef) is enough, the
> > > message is printed only when it's enabled based on check in
> > > __btrfsic_submit_bio "if (!btrfsic_is_initialized) return", where the
> > > rest of the function does all the verification.
> > 
> > Yes.  We need mount option 'check_int' or 'check_int_data' to  trigger
> > this check-integrity warning.
> 
> So the mount options need to be checked here as well.

We just need to add the mount option(check_int/check_int_data) to
changelog

when CONFIG_BTRFS_FS_CHECK_INTEGRITY=y and the disk with WCE=0.
=>
when CONFIG_BTRFS_FS_CHECK_INTEGRITY=y , and mount
option(check_int/check_int_data), and the disk with WCE=0.


The check of mount option(check_int/check_int_data) is done later
inside btrfsic_submit_bio. No necessary to check mount
option(check_int/check_int_data) here, we just need to match
submit_bio(linux/bio.h).

#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
void btrfsic_submit_bio(struct bio *bio);
int btrfsic_submit_bio_wait(struct bio *bio);
#else
#define btrfsic_submit_bio submit_bio
#define btrfsic_submit_bio_wait submit_bio_wait
#endif

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/11/04