Re: f2fs bug: Unable to mount big volumes in kernel 4.5

[Chao Yu <chao2.yu@samsung.com>]

Hi,

> -----Original Message-----
> From: Matthias Prager [mailto:linux@matthiasprager.de]
> Sent: Tuesday, March 22, 2016 6:56 AM
> To: David Gnedt; Chao Yu; 'Jaegeuk Kim'
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Subject: Re: f2fs bug: Unable to mount big volumes in kernel 4.5
> 
> Hello everyone,
> 
> if there really is a suboptimal/faulty alignment being done by
> f2fs-tools <=1.6.0 (and I haven't done the math, so I'm just assuming),
> wouldn't it be prudent to include a modified kernel patch, which allows
> for mounting of older filesystems, but puts out a warning in dmesg which
> advises the user to run fsck.f2fs some time in the future?

I agree with that.

Thanks,

> 
> ---
> Matthias
> 
> Am 21.03.2016 um 21:58 schrieb David Gnedt:
> > Hello,
> >
> >> Following commit in dev branch of f2fs-tools has fixed this issue, could you
> > test this
> >> patch firstly?
> >> ("mkfs.f2fs: set segment_count in super block correctly")
> >
> > Sorry, I cannot recreate the volume on the 8TB Seagate drive right now, but I
> > did a test with a loopback device of equal size.
> >
> > Should I be worried about the changes in mkfs.f2fs since 1.6.0? Would it be
> > suggested to recreate the filesystem? Or is it maybe possible to manually fix it?
> > If it is really only the alignment, I think it shouldn't matter for SMR drives,
> > as they are not using constant size zones anyway, so misalignment cannot be
> > avoided with f2fs.
> >
> >>> Could you test the attached patch?
> >
> > I did a roundup test of all kernel/f2fs-tools version I thought that make sense.
> > I hope the patch will be included in upcoming mainline kernels.
> >
> > Short summary:
> > --------------
> > Filesystems created with a recent dev version of f2fs-tools work without any
> > problems and don't need the f2fs kernel patch.
> > Filesystems created with older f2fs-tools need the f2fs kernel patch to mount
> > correctly.
> > I guess that is exactly what everyone expected to be the outcome.
> >
> > Full details:
> > -------------
> > f2fs-tools D:  release 1.6.0 (Seagate SMR drive)
> > f2fs-tools L1: release 1.6.0 (Loopback)
> > f2fs-tools L2: 2016-01-08 mkfs.f2fs: introduce zone align for main area (Loopback)
> > f2fs-tools L3: 2016-03-16 mkfs.f2fs: set segment_count in super block correctly
> > (Loopback)
> >
> > Test procedure:
> > $ truncate -s 8001559724032 f2fs-tools-1.6.0.img
> > $ losetup -f f2fs-tools-1.6.0.img
> > $ mkfs.f2fs -s64 -t0 -a0 /dev/loop0
> > $ mount -t f2fs -onoinline_data,noatime,flush_merge,no_heap,ro /dev/loop0 /mnt
> > $ umount /mnt
> >
> > Kernel: Linux 4.4.6 x86_64
> > f2fs-tools D:  Works
> > f2fs-tools L1: Works
> > f2fs-tools L2: Works
> > f2fs-tools L3: Works
> >
> > Kernel: Linux 4.5.0 x86_64
> > f2fs-tools D:  Failed -> Same errors as before
> > f2fs-tools L1: Failed -> Same errors as before
> > f2fs-tools L2: Failed -> Same errors as before
> > f2fs-tools L3: Works
> >
> > Kernel: Linux 4.5.0+patch x86_64
> > f2fs-tools D:  Works
> > f2fs-tools L1: Works
> > f2fs-tools L2: Works
> > f2fs-tools L3: Works
> >
> > Best regards,
> > David Gnedt
> >



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