Shaun Reich posted on Sat, 31 May 2014 23:51:26 -0400 as excerpted: > at some point, my /home randomly(?) went into -ro as i noticed writes > were not working. Checked dmesg which had some backtraces which i > ignored. So I simply rebooted, only to find out it wouldn't come back. > > so now my /home is stuck on here, I was literally going to do my round > of backups tonight. It's not extremely critical..but to reproduce my > data it'll still be several hours of lost time..and the annoyances of > redoing it. > > mounting results in this, as below. mounting recovery doesn't help. > mounting ro recovery doesn't help. btrfs fsck basically reaffirms what I > know so far, that I'm screwed because my superblock is bad. > > show super: http://pastie.org/private/b1k2famcfmtquaqgpyfozg mount > dmesg: http://pastie.org/private/8zsczfustrmeg6a2bbfxag > > btrfs-find-root: http://bpaste.net/show/326346
Hi, Shaun. KDE user here, gentoo, USE=-semantic-desktop, active on the kde general and linux lists (as well as here and the gentoo lists). =:^) How do you know it's a bad superblock? While I'm not a dev just a list regular, show-super looks reasonable from here, and find-root does find what appears to be a good root. From here the problem seems to be a bad ctree (of several), not a bad superblock. First thing to try is mounting with nospace_cache. If that works, try mounting with clear_cache and letting it work for a bit to rebuild. If that doesn't work, it may simply be the log tree. btrfs-zero-log is used to fix that, but before you try that, read this entry in the FAQ and follow the instructions for making a filesystem image to turn in to the devs to help them fix such problems, and consider making a backup of the damaged filesystem using dd/ddrescue, since the warning about making it possibly more difficult to recover if this is NOT the problem applies: https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#I_can.27t_mount_my_filesystem.2C_and_I_get_a_kernel_oops.21 With luck one of those options will help. I know I had a space_cache issue here myself, some time ago. I've not had to run zero-log, but I've seen a number of posters who found it helped. Another thing to try is mounting recovery,ro. A number of people have reported that would work when simple recovery wouldn't, because when it was writable btrfs would immediately try to fix the problem and immediately fail. Beyond that, you'll need more expert help. But most of the time one of those three works, so with luck... -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
