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

[Matthias Prager <linux@matthiasprager.de>]

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?

---
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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