RE: Can anyone boot a system using btrfs root with linux 3.14 or newer?

["Пламен Петров" <plamen@petrovi.no-ip.info>]

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> -----Original Message-----
> From: Marc MERLIN [mailto:marc@merlins.org]
> Sent: Wednesday, April 23, 2014 10:16 PM
> To: Пламен Петров
> Cc: linux-btrfs@vger.kernel.org
> Subject: Re: Can anyone boot a system using btrfs root with linux 3.14 or
> newer?
> 
> On Wed, Apr 23, 2014 at 10:06:12PM +0300, Пламен Петров wrote:
> > Just to clarify - I am using a monolithic kernel built from source, and it has all
> the stuff it needs to support built-in, and then some. And no modules.
> > The sources I'm using are the vanilla kernels from Linus and Greg KH
> downloaded from kernel.org.
> 
> Ok.
> 
> > Check out the attached config I am using - it’s a kernel I'm running on one
> server and a couple of virtual machines.
> 
> That's the working .config.
> I suggest you diff that one with the new one you have for 3.14
> 
> > Until now - copying said config and doing a "make oldconfig" or "make
> olddefconfig" and compiling-then-booting worked fine.
> 
> This should indeed work, this is what I do too.
> 
> So now, we're kind of guessing. To save us all time, could you capture a serial
> console boot from the running 3.13 and then the failing 3.14.

Well, for the details - see for example here:
https://bugzilla.kernel.org/attachment.cgi?id=133111
how does a 3.14.1 built the way described earlier fails.

And for that matter - see the whole bugzilla bug entry - I went on and bisected this, using the linux-stable git tree, and after that landed me on the commit that introduces some "shiny new btrfs feature" for 3.14 - I decided my git bisection has gone wrong. And because I reported it on April 17-th and since then there has been no activity on the bugzilla entry besides me updating it - I posted my problem here, for more eyes to see.

> 
> My guess is that if you diff both you'll likely find what went wrong, but if not
> you can post here.

See the result of "diff config-v3.14.1-mix64 config-v3.13.11-mix64" in the attached file.

> 
> As for the btrfs FS format, it has not changed in a way that new kernels
> wouldn't be able to mount an FS from a year ago or more.

Good to know! Thanks!

> 
> Marc
---------------------------------
Plamen Petrov

[-- Attachment #2: diff-3.14.1-to-3.13.11.txt --]
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 diff config-v3.14.1-mix64 config-v3.13.11-mix64
3c3
< # Linux/x86 3.14.1 Kernel Configuration
---
> # Linux/x86 3.13.11 Kernel Configuration
155a156
> # CONFIG_UIDGID_STRICT_TYPE_CHECKS is not set
230,234d230
< CONFIG_HAVE_CC_STACKPROTECTOR=y
< # CONFIG_CC_STACKPROTECTOR is not set
< CONFIG_CC_STACKPROTECTOR_NONE=y
< # CONFIG_CC_STACKPROTECTOR_REGULAR is not set
< # CONFIG_CC_STACKPROTECTOR_STRONG is not set
309d304
< # CONFIG_XEN_PVH is not set
358a354
> CONFIG_MICROCODE_INTEL_LIB=y
407d402
< # CONFIG_ZSMALLOC is not set
419a415
> # CONFIG_CC_STACKPROTECTOR is not set
430d425
< # CONFIG_RANDOMIZE_BASE is not set
762,763d756
< # CONFIG_NET_SCH_HHF is not set
< # CONFIG_NET_SCH_PIE is not set
794,795c787
< # CONFIG_CGROUP_NET_PRIO is not set
< # CONFIG_CGROUP_NET_CLASSID is not set
---
> # CONFIG_NETPRIO_CGROUP is not set
944d935
< # CONFIG_GENWQE is not set
997a989
> # CONFIG_SCSI_AIC7XXX_OLD is not set
1158d1149
< CONFIG_DM_BUFIO=y
1256d1246
< # CONFIG_I40EVF is not set
1489d1478
< CONFIG_ARCH_MIGHT_HAVE_PC_SERIO=y
1608d1596
< # CONFIG_I2C_DESIGNWARE_PLATFORM is not set
1622d1609
< # CONFIG_I2C_ROBOTFUZZ_OSIF is not set
1807a1795
> # CONFIG_CPU_THERMAL is not set
1811d1798
< # CONFIG_ACPI_INT3403_THERMAL is not set
1851d1837
< # CONFIG_MFD_MAX14577 is not set
1872d1857
< # CONFIG_MFD_LP3943 is not set
1904d1888
< CONFIG_INTEL_GTT=y
1928d1911
< # CONFIG_DRM_I915_UMS is not set
1940d1922
< # CONFIG_DRM_BOCHS is not set
1978d1959
< # CONFIG_FB_OPENCORES is not set
2080a2062
> # CONFIG_HID_LOGITECH_DJ is not set
2184d2165
< # CONFIG_USB_MUSB_HDRC is not set
2186d2166
< # CONFIG_USB_DWC2 is not set
2225d2204
< # CONFIG_USB_OTG_FSM is not set
2269d2247
< # CONFIG_RTC_DRV_ISL12057 is not set
2403d2380
< CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y
2450a2428
> CONFIG_GENERIC_ACL=y
2604d2581
< CONFIG_PANIC_TIMEOUT=0