Hi all,
On Wed, 29 Nov 2023 12:09:30 +0100 Jan Kara <jack@xxxxxxx> wrote:
>
> On Tue 28-11-23 14:33:44, Nathan Chancellor wrote:
> > Hi Stephen (and other maintainers),
> >
> > On Mon, Nov 27, 2023 at 09:20:01AM +1100, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > Today's linux-next merge of the vfs-brauner tree got a conflict in:
> > >
> > > fs/btrfs/super.c
> > >
> > > between commit:
> > >
> > > 2f2cfead5107 ("btrfs: remove old mount API code")
> > >
> > > from the btrfs tree and commit:
> > >
> > > ead622674df5 ("btrfs: Do not restrict writes to btrfs devices")
> > >
> > > from the vfs-brauner tree.
> > >
> > > I fixed it up (the former removed the funtion updated by the latter, but
> > > a further fix may be required to implement the intent of the latter?)
> >
> > Yes, the lack of ead622674df5 appears to cause issues with mounting
> > btrfs volumes on at least next-20231128 due to the presence of commit
> > 6f861765464f ("fs: Block writes to mounted block devices"). In QEMU, I
> > can see:
> >
> > :: running early hook [udev]
> > Warning: /lib/modules/6.7.0-rc3-next-20231128/modules.devname not found - ignoring
> > Starting systemd-udevd version 252.5-1-arch
> > :: running hook [udev]
> > :: Triggering uevents...
> > :: running hook [keymap]
> > :: Loading keymap...kbd_mode: KDSKBMODE: Inappropriate ioctl for device
> > done.
> > :: performing fsck on '/dev/vda2'
> > :: mounting '/dev/vda2' on real root
> > mount: /new_root: wrong fs type, bad option, bad superblock on /dev/vda2, missing codepage or helper program, or other error.
> > dmesg(1) may have more information after failed mount system call.
> > You are now being dropped into an emergency shell.
> > sh: can't access tty; job control turned off
> > [rootfs ]#
> >
> > The following diff allows my VM to boot properly but I am not sure if
> > there is a better or more proper fix (I am already out of my element
> > heh). If a proper merge solution cannot be found quickly, can
> > 6f861765464f be reverted in the meantime so that all my machines with
> > btrfs can boot properly? :)
> >
> > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> > index 99d10a25a579..23db0306b8ef 100644
> > --- a/fs/btrfs/super.c
> > +++ b/fs/btrfs/super.c
> > @@ -299,6 +299,7 @@ static int btrfs_parse_param(struct fs_context *fc,
> > case Opt_device: {
> > struct btrfs_device *device;
> > blk_mode_t mode = sb_open_mode(fc->sb_flags);
> > + mode &= ~BLK_OPEN_RESTRICT_WRITES;
> >
> > mutex_lock(&uuid_mutex);
> > device = btrfs_scan_one_device(param->string, mode, false);
> > @@ -1801,6 +1802,8 @@ static int btrfs_get_tree_super(struct fs_context *fc)
> > blk_mode_t mode = sb_open_mode(fc->sb_flags);
> > int ret;
> >
> > + mode &= ~BLK_OPEN_RESTRICT_WRITES;
> > +
> > btrfs_ctx_to_info(fs_info, ctx);
> > mutex_lock(&uuid_mutex);
>
> This looks like the proper resolution. Basically btrfs needs to strip
> BLK_OPEN_RESTRICT_WRITES from the mode provided by sb_open_mode(). Thanks
> for writing it!
I have added this patch as a merge fix from today.
--
Cheers,
Stephen Rothwell
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