From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: btrfs error after using kernel 3.0-rc1 Date: Wed, 01 Jun 2011 17:48:37 -0400 Message-ID: <1306964572-sup-4244@shiny> References: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Cc: linux-btrfs To: "Fajar A. Nugraha" Return-path: In-reply-to: List-ID: Excerpts from Fajar A. Nugraha's message of 2011-06-01 08:22:40 -0400: > On Wed, Jun 1, 2011 at 6:06 AM, Fajar A. Nugraha wro= te: > > While using btrfs as root on kernel 3.0-rc1, there was some errors = (I > > wasn't able to capture the error) that forced me to do hard reset. > > > > Now during startup system drops to busybox shell because it's unabl= e > > to mount root partition. > > Is there a way to recover the data, as at least grub2 was still hap= py > > enough to load kernel and initrd (both of which located on the same > > btrfs partition)? > > > > This is what dmesg says > > > > [ =C2=A0 =C2=A04.536798] device label SSD-ROOT devid 1 transid 3824= 5 /dev/sda2 > > [ =C2=A0 =C2=A09.552086] device label SSD-ROOT devid 1 transid 3824= 5 > > /dev/disk/by-label/SSD-ROOT > > [ =C2=A0 =C2=A09.554563] btrfs: disk space caching is enabled > > [ =C2=A0 =C2=A09.564301] parent transid verify failed on 44040192 w= anted 38240 found 32526 > > [ =C2=A0 =C2=A09.564535] parent transid verify failed on 44040192 w= anted 38240 found 32526 > > [ =C2=A0 =C2=A09.564778] parent transid verify failed on 44040192 w= anted 38240 found 32526 > > [ =C2=A0 =C2=A09.575679] parent transid verify failed on 44052480 w= anted 38240 found 31547 > > [ =C2=A0 =C2=A09.575904] parent transid verify failed on 44052480 w= anted 38240 found 31547 > > [ =C2=A0 =C2=A09.576176] parent transid verify failed on 44052480 w= anted 38240 found 31547 > > [ =C2=A0 =C2=A09.586121] parent transid verify failed on 44064768 w= anted 38240 found 34145 > > [ =C2=A0 =C2=A09.586319] parent transid verify failed on 44064768 w= anted 38240 found 34145 > > [ =C2=A0 =C2=A09.586515] parent transid verify failed on 44064768 w= anted 38240 found 34145 > > [ =C2=A0 =C2=A09.587027] parent transid verify failed on 44068864 w= anted 38240 found 34476 > > [ =C2=A0 =C2=A09.589732] Btrfs detected SSD devices, enabling SSD m= ode > > [ =C2=A0 =C2=A09.592923] block group 29360128 has an wrong amount o= f free space > > [ =C2=A0 =C2=A09.592959] btrfs: failed to load free space cache for= block group 29360128 >=20 >=20 > For anyone who got the same problem, >=20 > I was finally able to mount the fs using Ubuntu Natty's > 2.6.38-8-generic (the one on live CD). > Previously I tried using 2.6.38-9-generic and and 3.0-rc1, none works= =2E > Now I'm copying the files somewhere else before reinstalling this > system. The tools have a command to zero out the btrfs log tree, that would hav= e allowed you to mount. Do you still have the busted FS? Thanks a lot for this bug report, I'll try to reproduce it. >=20 > On another note, does anybody know how btrfs allocates ID for subvols= ? > It doesn't seem to reuse deleted subvol's ID. What happens when the > last subvol ID is 999? >=20 We don't reuse the ids for subvols or snapshots, but we can have a little less than 2^64 of them. An id can be reused as long as there ar= e no blocks with refs for it in the extent allocation tree, but that need= s to be checked before we reuse it. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html