On Sun, 2015-02-22 at 15:19 -0500, Douglas Gilbert wrote: > On 15-02-22 11:41 AM, Christoph Hellwig wrote: > > On Sat, Feb 14, 2015 at 03:27:40AM +0000, Nicholas A. Bellinger wrote: > >> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > >> > >> This patch adds a sbc_check_dpofua() function that performs sanity > >> checks for DPO/FUA command bits. > >> > >> It introduces checks to fail when either bit is set, but the backend > >> device is not advertising support for them. > >> > >> It also moves the existing cmd->se_cmd_flags |= SCF_FUA assignement > >> into the new helper function. > > > > This causes I/O errors with ext4 on tcm_loop on what seems to be the first > > journal commit: > > > > [ 41.818126] EXT4-fs (sdc): mounted filesystem with ordered data mode. Opts: (null) > > [ 48.919107] Got CDB: 0x2a with FUA bit set, but device does not advertise support for FUA write Where is this coming from? It's not a message I can find in the current kernel. > > [ 48.920245] sd 3:0:0:0: [sdc] tag#113 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE > > [ 48.921219] sd 3:0:0:0: [sdc] tag#113 Sense Key : Illegal Request [current] > > [ 48.921980] sd 3:0:0:0: [sdc] tag#113 Add. Sense: Invalid field in cdb > > Setting (or clearing) the FUA bit on READ or WRITE commands > does not cause an error according to sbc4r05 irrespective of > the LU's support for volatile and non-volatile caches. I'm > pretty sure that hasn't changed recently (say 15 years). Well, firstly, that doesn't change the fact that sending FUA commands to a non-FUA supporting device is a bug because the stable storage guarantee the filesystem is relying on is broken. However, your characterisation of the standards isn't quite correct: you've forgotten SAT. SAT allows a non FUA supporting ATA device to return illegal request ... and I bet this is what's happening. James -- 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
