Filed bug here with more details and complete dmesg attached: https://bugzilla.kernel.org/show_bug.cgi?id=87131 kernel-3.18.0-0.rc2.git1.1.fc22.x86_64 SUMMARY: After umount returning to prompt, and physical disconnected 2x devices (btrfs raid1 on raw devices), I get a backtrace with some scary messages. Here are some snippets: [10570.371285] BTRFS: error (device sdc) in btrfs_commit_transaction:1917: errno=-5 IO failure (Error while writing out transaction) [10570.372426] BTRFS info (device sdc): forced readonly [10570.372432] BTRFS warning (device sdc): Skipping commit of aborted transaction. [10570.372456] BTRFS: Transaction aborted (error -5) [10570.372807] BTRFS: error (device sdc) in cleanup_transaction:1599: errno=-5 IO failure [10570.373960] BTRFS info (device sdc): delayed_refs has NO entry After reboot, kernel shows both devids have the same generation. btrfs check comes up clean. mount also has no complaints, and mounts rw. Chris Murphy-- 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