Hello! I found the original bug and proposed the original patch to the kernel SCSI guys. Here's some context:
The SCSI flush command was being treated by a zero-byte write, which means that if an error was returned, you wouldn't catch it until a subsequent write (or flush). The way writes work is that all possible bytes are written, and if something bad happens, an error bubbles out on the next write attempt. This holds true even for a zero-byte write. This means that before this bug, to guarantee durability you had to flush twice (and verify both were error-free). I'm working on a storage appliance that relies on the fact that a single flush command guarantees a write made durably to a SCSI device. I'm sure many other storage products rely on this behavior, too. I'm not sure why certain USB drives are failing in the flush path on unmount. Since the flush bug existed for such a long time, I suspect certain drivers coded around this behavior, and now that it is correct we are seeing new bugs exposed. Based on the simplicity and obviousness of our patch for the flush bug, it would really be ideal to diagnose this further rather than reverting. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1366538 Title: Synchronisation/close /dev/sdX: i/o error on target host Status in linux package in Ubuntu: Triaged Status in linux source package in Trusty: Triaged Status in linux source package in Utopic: Triaged Status in linux source package in Vivid: Triaged Bug description: Ubuntu 14.04.1 x86-64 wanting to unmout a pata drive (usb attached), I get this (title) "Warning from libparted" when gparted launches. Same issue with another pc x86-64 Errors retries then ignore, shred /dev/sdi fails: shred: /dev/sdi : pass 1/2 (random)… shred: /dev/sdi : pass 1/2 (random)…231MiB/94GiB 0 % shred: /dev/sdi : failure of fdatasync: i/o error on target host I reached to shred the drive from a 12.04.4 i386 pc with no error. Sep 7 15:07:08 nux kernel: [261448.072475] usb 5-1: new high-speed USB device number 10 using xhci_hcd Sep 7 15:07:09 nux kernel: [261448.202999] usb 5-1: New USB device found, idVendor=04cf, idProduct=8818 Sep 7 15:07:09 nux kernel: [261448.203008] usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 Sep 7 15:07:09 nux kernel: [261448.203013] usb 5-1: Product: USB Mass Storage Device Sep 7 15:07:09 nux kernel: [261448.203018] usb 5-1: Manufacturer: Myson Century, Inc. Sep 7 15:07:09 nux kernel: [261448.205463] usb-storage 5-1:1.0: USB Mass Storage device detected Sep 7 15:07:09 nux kernel: [261448.205673] scsi20 : usb-storage 5-1:1.0 Sep 7 15:07:10 nux kernel: [261449.206849] scsi 20:0:0:0: Direct-Access HTS72101 0G9AT00 MCZO PQ: 0 ANSI: 0 CCS Sep 7 15:07:10 nux kernel: [261449.207763] sd 20:0:0:0: Attached scsi generic sg7 type 0 Sep 7 15:07:10 nux kernel: [261449.207901] sd 20:0:0:0: [sdi] 195371568 512-byte logical blocks: (100 GB/93.1 GiB) Sep 7 15:07:10 nux kernel: [261449.208068] sd 20:0:0:0: [sdi] Write Protect is off Sep 7 15:07:10 nux kernel: [261449.208074] sd 20:0:0:0: [sdi] Mode Sense: 00 14 00 00 Sep 7 15:07:10 nux kernel: [261449.208280] sd 20:0:0:0: [sdi] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Sep 7 15:07:10 nux kernel: [261449.555232] sdi: unknown partition table Sep 7 15:07:10 nux kernel: [261449.555926] sd 20:0:0:0: [sdi] Attached SCSI disk Sep 7 15:07:43 nux kernel: [261482.219026] end_request: critical target error, dev sdi, sector 0 Sep 7 15:07:52 nux kernel: [261492.015180] end_request: critical target error, dev sdi, sector 0 Sep 7 15:07:55 nux kernel: [261494.261159] end_request: critical target error, dev sdi, sector 0 Sep 7 15:16:23 nux kernel: [262003.027005] end_request: critical target error, dev sdi, sector 0 Sep 7 15:16:35 nux kernel: [262014.215352] end_request: critical target error, dev sdi, sector 0 Sep 7 15:16:35 nux kernel: [262014.859651] end_request: critical target error, dev sdi, sector 0 [EDIT: Once shreded, no error on the i386, but still same error on the 2 x86-64] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1366538/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
