On Tue, 10 Dec 2013, Sarah Sharp wrote: > In order to stress test the uas driver (next-gen USB storage driver), I > decided to run some tests with a USB 3.0 storage device with four 10GB > partitions: BTRFS, ext3, ext4, and fat32. > > It seems that BTRFS doesn't handle unexpected USB disconnect very well. > Is that expected behavior? > > The BTRFS partition was created on an Ubuntu 13.10 system, with > btrfs-tools version 0.19+20130705-1. > > On 3.12-rc6, if all partitions are mounted, and I yank the USB cable, > the BTRFS filesystem still shows up as mounted. If I yank it multiple > times, sometimes it's listed twice when the device is disconnected: > > /dev/sdb3 on /media/sarah/9f21ef28-0eac-4736-9964-db5378b877e4 type btrfs (rw,nosuid,nodev,uhelper=udisks2) > /dev/sdc3 on /media/sarah/9f21ef28-0eac-4736-9964-db5378b877e41 type btrfs (rw,nosuid,nodev,uhelper=udisks2) > > Sometimes (but not always) when I plug it back in, I can get /dev/sdc3 > listed twice: > > /dev/sdb3 on /media/sarah/9f21ef28-0eac-4736-9964-db5378b877e4 type btrfs (rw,nosuid,nodev,uhelper=udisks2) > /dev/sdc3 on /media/sarah/9f21ef28-0eac-4736-9964-db5378b877e42 type btrfs (rw,nosuid,nodev,uhelper=udisks2) > /dev/sdc1 on /media/sarah/ext3-part type ext3 (rw,nosuid,nodev,uhelper=udisks2) > /dev/sdc2 on /media/sarah/ext4-part type ext4 (rw,nosuid,nodev,uhelper=udisks2) > /dev/sdc4 on /media/sarah/fat32-part type vfat (rw,nosuid,nodev,uid=1000,gid=1000,shortname=mixed,dmask=0077,utf8=1,showexec,flush,uhelper=udisks2) > /dev/sdc3 on /media/sarah/9f21ef28-0eac-4736-9964-db5378b877e41 type btrfs (rw,nosuid,nodev,uhelper=udisks2) > > On 3.13-rc1, the btrfs partion from the disconnected USB device > continues to be listed as mounted. Yanking the cable produces some > additional oops messages. It also produced a couple hard-hangs. > Unfortunately, I didn't capture the dmesg during the hard-hangs, so I > can't tell for sure which driver is to blame (uas, btrfs, or xhci). Does this happen with usb-storage instead of uas? What about with ehci-hcd instead of xhci-hcd? And just to be exotic, what about with dummy-hcd and the uas or g_mass_storage gadget driver? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
