Hi Nicholas,
I have found a regression in the LIO iSCSI targets that causes I/Os to
fail. I performed a `git bisect` between Linux v3.19 and v4.0-rc4 that
showed that the regression is caused by the following commit:
fde9f50f80fe89a9115b4bfa773017272597d85d is the first bad commit
commit fde9f50f80fe89a9115b4bfa773017272597d85d
Author: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Date: Fri Feb 13 23:28:27 2015 +0000
target: Add sanity checks for DPO/FUA bit usage
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.
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
:040000 040000 ea7ec2dcaf1f052d260ef595576debd31b50ac72 39116e63d803b5710a385f3f47bad4a74262defc M drivers
Here are the steps I follow to trigger the bug:
1/ create an iSCSI target with a block backstore
2/ login to the target with open-iscsi
3/ format the mapped LUN with an ext4 file system
4/ mount the file system
5/ create some files with `touch`
The file creation fails because the file system is remounted
read-only due to I/O errors. Errors are displayed in `dmesg` output on
both the initiator and target:
== initiator ==
[ 1564.577302] scsi6 : iSCSI Initiator over TCP/IP
[ 1564.831189] scsi 6:0:0:0: Direct-Access LIO-ORG block1 4.0 PQ: 0 ANSI: 5
[ 1564.832221] sd 6:0:0:0: Attached scsi generic sg4 type 0
[ 1564.832933] sd 6:0:0:0: [sdd] 209715200 512-byte logical blocks: (107 GB/100 GiB)
[ 1564.832935] sd 6:0:0:0: [sdd] 4096-byte physical blocks
[ 1564.834061] sd 6:0:0:0: [sdd] Write Protect is off
[ 1564.834063] sd 6:0:0:0: [sdd] Mode Sense: 43 00 10 08
[ 1564.834429] sd 6:0:0:0: [sdd] Write cache: enabled, read cache: enabled, supports DPO and FUA
[ 1564.847764] sdd: unknown partition table
[ 1564.850051] sd 6:0:0:0: [sdd] Attached SCSI disk
[ 1584.684077] sdd: unknown partition table
[ 1593.360501] EXT4-fs (sdd): mounted filesystem with ordered data mode. Opts: (null)
[ 1600.709370] sd 6:0:0:0: [sdd] Invalid command failure
[ 1600.709377] sd 6:0:0:0: [sdd]
[ 1600.709378] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[ 1600.709380] sd 6:0:0:0: [sdd]
[ 1600.709382] Sense Key : Illegal Request [current]
[ 1600.709384] sd 6:0:0:0: [sdd]
[ 1600.709386] Add. Sense: Invalid field in cdb
[ 1600.709387] sd 6:0:0:0: [sdd] CDB:
[ 1600.709389] Write(10): 2a 08 06 44 00 20 00 00 08 00
[ 1600.709393] end_request: critical target error, dev sdd, sector 105119776
[ 1600.709397] end_request: critical target error, dev sdd, sector 105119776
[ 1600.709417] Aborting journal on device sdd-8.
[ 1601.068860] EXT4-fs error (device sdd): ext4_journal_check_start:56: Detected aborted journal
[ 1601.068864] EXT4-fs (sdd): Remounting filesystem read-only
[ 1648.316509] EXT4-fs error (device sdd): ext4_put_super:790: Couldn't clean up the journal
[ 1652.339136] sd 6:0:0:0: [sdd] Synchronizing SCSI cache
== target ==
[ 116.885007] TARGET_CORE[iSCSI]: Unsupported SCSI Opcode 0x85, sending CHECK_CONDITION.
[ 116.894395] TARGET_CORE[iSCSI]: Unsupported SCSI Opcode 0x85, sending CHECK_CONDITION.
[ 152.649728] Got CDB: 0x2a with FUA bit set, but device does not advertise support for FUA write
Feel free to ask if you want me to provide more information or
perform additional tests.
With best regards,
--
Christophe Vu-Brugier
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