Re: [PATCH] btrfs: add dmesg output when mounting and unmounting

[David Sterba <dsterba@suse.cz>]

On Tue, Nov 14, 2023 at 06:37:15AM +1030, Qu Wenruo wrote:
> 
> 
> On 2023/11/14 04:15, David Sterba wrote:
> > On Thu, Nov 02, 2023 at 07:54:50AM +1030, Qu Wenruo wrote:
> >> There is a feature request to add dmesg output when unmounting a btrfs.
> >>
> >> There are several alternative methods to do the same thing, but with
> >> their problems:
> >>
> >> - Use eBPF to watch btrfs_put_super()/open_ctree()
> >>    Not end user friendly, they have to dip their head into the source
> >>    code.
> >>
> >> - Watch for /sys/fs/<uuid>/
> >>    This is way more simpler, but still requires some simple device -> uuid
> >>    lookups.
> >>    And a script needs to use inotify to watch /sys/fs/.
> >>
> >> Compared to all these, directly outputting the information into dmesg
> >> would be the most simple one, with both device and UUID included.
> >>
> >> And since we're here, also add the output when mounting a btrfs, to keep
> >> the dmesg paired.
> >>
> >> Now mounting a btrfs with all default mkfs options would look like this:
> >>
> >> [   81.906566] BTRFS info (device dm-8): mounting filesystem 633b5c16-afe3-4b79-b195-138fe145e4f2
> >> [   81.907494] BTRFS info (device dm-8): using crc32c (crc32c-intel) checksum algorithm
> >> [   81.908258] BTRFS info (device dm-8): using free space tree
> >> [   81.912644] BTRFS info (device dm-8): auto enabling async discard
> >> [   81.913277] BTRFS info (device dm-8): checking UUID tree
> >> [   91.668256] BTRFS info (device dm-8): unmounting filesystem 633b5c16-afe3-4b79-b195-138fe145e4f2
> >
> > On a fresh look, I' suggest to write the messages like
> >
> > BTRFS info (...): first mount of filesystem UUID
> > ...
> > BTRFS info (...): last umount of filesystem UUID
> >
> > This is not for each mount so it's slightly confusing.
> >
> Sure, I'm totally fine to change the words.
> 
> Do I need to resend or the change is small enough to get updated in the
> branch?

No need to resend for such changes, is more for the feedback and sanity
check.