On Sat, Dec 26, 2015 at 4:38 AM, <covici@xxxxxxxxxxxxxx> wrote: > Duncan <1i5t5.duncan@xxxxxxx> wrote: > >> covici posted on Sat, 26 Dec 2015 02:29:11 -0500 as excerpted: >> >> > Chris Murphy <lists@xxxxxxxxxxxxxxxxx> wrote: >> > >> >> If you can post the entire dmesg somewhere that'd be useful. MUAs tend >> >> to wrap that text and make it unreadable on list. I think the problems >> >> with your volume happened before the messages, but it's hard to say. >> >> Also, a generation of nearly 5000 is not that new? >> > >> > The file system was only a few days old. It was on an lvm volume group >> > which consisted of two ssd drives, so I am not sure what you are saying >> > about lvm cache -- how could I do anything different? >> > >> >> On another thread someone said you probably need to specify the device >> >> to mount when using Btrfs and lvmcache? And the device to specify is >> >> the combined HDD+SSD logical device, for lvmcache that's the "cache >> >> LV", which is the OriginLV + CachePoolLV. If Btrfs decides to mount the >> >> origin, it can result in corruption. >> > >> > See above. >> >> I think he mixed up two threads and thought you were running lvm-cache, >> not just regular lvm, which should be good unless you're exposing lvm >> snapshots and thus letting btrfs see multiple supposed UUIDs that aren't >> actually universal. Since btrfs is multi-device and uses the UUID to >> track which devices belong to it (because they're _supposed_ to be >> universally unique, it's even in the _name_!), if it sees the same UUID >> it'll consider it part of the same filesystem, thus potentially causing >> corruption if it's a snapshot or something that's not actually supposed >> to be part of the (current) filesystem. > > I found a few more log entries, perhaps these may be helpful to track > this down, or maybe prevent the filesystem from going read-only. No, you need to post the entire dmesg. The "cut here" part is maybe useful for a developer diagnosing Btrfs's response to the problem, but the problem, or the pre-problem, happened before this. -- Chris Murphy -- 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
