> -----Original Message----- > From: Marc MERLIN [mailto:marc@xxxxxxxxxxx] > Sent: Thursday, April 24, 2014 10:31 PM > To: Пламен Петров > Cc: linux-btrfs@xxxxxxxxxxxxxxx > Subject: Re: Can anyone boot a system using btrfs root with linux 3.14 or > newer? > > On Thu, Apr 24, 2014 at 09:51:30PM +0300, Пламен Петров wrote: > > So, here is what I did: > > My debug VM had: > > sda > > sda1 200 MB /boot - ext2 > > sda2 5 GB / - BTRFS > > sda3 5 GB / - XFS > > sda4 One extra partition used for mangling (XFS). > > > > sda2 and sda3 were mostly the same, except /etc/fstab, for obvious > reasons. > > > > I booted 3.14.1 using sda3 as root, and then tried mounting sda2. It went > OK, here is what dmesg said: > > [ 12.412465] Btrfs loaded > > [ 86.490078] BTRFS: device fsid 2ba08fbc-4b95-46cc-b638-299f16462620 > devid 1 transid 22 /dev/sda2 > > [ 86.492947] BTRFS info (device sda2): disk space caching is enabled > > [ 86.579155] BTRFS: creating UUID tree > > [ 86.748681] mount (1899) used greatest stack depth: 2560 bytes left > > Ok, that's good news. It indeed rules out that your new kernel cannot mount > an older btrfs filesystem. > > At this point, you may have a problem with the device not being available > when btrfs tries to mount it. Need a way to pinpoint the actual problem then. > > > From the above - the first obvious thing is that with 3.13.11 BTRFS gets > loaded much earlier in the boot process - that is why the second dmesg > dump is much larger, and both start at " Btrfs loaded" - mind you. > > > > Next was booting the BTRFS sda2 with 3.14.1. > > Sadly, it panicked again. So, no dmesg dump - just a screenshot. See the > attached file. > > So, what got changed during the 3.14 merge window, that messed up > booting for BTRFS partitions? > > Should I try building an "allyesconfig" kernel, in case something is messed > up with my kernel .configs? > > What do you think guys and galls? > > Anything you want me try - this is entirely disposable VM now, so I'll gladly > try everything you ask... > > So, I'm not sure how many people use btrfs built it vs as a module. Clearly the > code works for mounting your partition, but when built in the kernel, there > seems to be a timing issue. Yeah, and an issue that just popped up with kernels >= 3.14. If memory serves - I started using BTRFS on linux 3.6.x, and since then I followed exactly the same method of upgrading the kernel - described in this thread and in the bugzilla entry - and it always "Just Works" TM! > > For reference, you said this was the bug where you found the CL that causes > this change: > https://bugzilla.kernel.org/show_bug.cgi?id=74261 > > You said using rootwait as recommended by Chris Mason did not help. > > What output are you getting when you use this? The image file attached to my previous mail applies to both rootwait and no-rootwait cases. Result is always a kernel panic for 3.14.x on BTRFS root. All other filesystem/kernel combos just work either way. > > By the way, you should be able to define a pseudo serial port in your VM and > specify something like > console=tty0 console=ttyS0,38400n8 > on your boot command line. > This will give you serial console output in text that you can cut/paste/diff I will try and use this the next time. Thanks! --------------------------------- Plamen Petrov -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
