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There seems to be a bug in passing sense information to QLA HBAs, where the last 2 bytes of the sense data (ASC, ASCQ) are not copied to the low level sense buffer. We encountered this in ESX, which relies on these 2 bytes to parse the MISCOMPARE sense code (0xE1, 0x1D, 0x00). Bellow is a simple test to recreate this issue, but during vMotion operations (where VMs are moved from one host to another), this may cause the operation to fail leaving the VM in an inconsistent state. The test I ran to verify that we are indeed missing the bytes is the following: 1. Create a SCST based device 2. Expose the device to 2 ESX hosts 3. Format the device as VMFS5, create a test directory 4. From both hosts, I start writing to this directory (no VMs involved, just write normal files) At this stage, both ESX hosts try to take access to the directory. The VMFS filesystem contains a per-directory lock which is managed by COMPARE AND WRITE command. Each ESX will attempt to change the VMFS lock location from unlocked to locked to create the new file. Obviously there are bound to be failures (which are equivalent to programming locking conflicts), these are reported by the MISCOMPARE sense code. Upon these MISCOMPARE errors, the host will re-try taking the lock until it succeeds, and will then proceed to perform the write operation on the directory. Due to the bug in copying the sense buffer from the SCST core to the QLA ctio, instead of the full sense code, only the key (0xE) is sent, and ESX does not know how to handle it resulting in IO error. Here are the errors as they appear on the command line: /vmfs/volumes/54a297c4-ca5af1cc-7f94-002219d20f28/ats_test # ./open_close_test-esx2.sh ./open_close_test-esx2.sh: line 8: can't create ats_fileoptest-esx2_1.txt: Input/output error ./open_close_test-esx2.sh: line 8: can't create ats_fileoptest-esx2_21.txt: Input/output error ./open_close_test-esx2.sh: line 8: can't create ats_fileoptest-esx2_110.txt: Input/output error ./open_close_test-esx2.sh: line 8: can't create ats_fileoptest-esx2_111.txt: Input/output error In the /var/log/vmkernel.log, we can see that the sense information is missing (0xE, 0x0, 0x0) instead of (0xE, 0x1D, 0x0). 2014-12-30T12:13:20.714Z cpu6:33519)ScsiDeviceIO: 2338: Cmd(0x412e84f957c0) 0x89, CmdSN 0x234d from world 519051 to dev "eui.0024f400d5020007" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x0 0x0. 2014-12-30T12:13:20.766Z cpu6:33519)ScsiDeviceIO: 2338: Cmd(0x412e84f91d00) 0x89, CmdSN 0x2350 from world 519051 to dev "eui.0024f400d5020007" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x0 0x0. 2014-12-30T12:13:20.766Z cpu6:33519)ScsiDeviceIO: 2338: Cmd(0x412e80449fc0) 0x89, CmdSN 0x234f from world 519051 to dev "eui.0024f400d5020007" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0xe 0x0 0x0. This patch fixes this issue, the test will run without a problem with the fix (no IO errors, all the files are properly written to the directory). Signed-off-by: Shahar Salzman <shahar.salzman@kaminario.com> Reviewed-by: Eran Mann <eran.mann@kaminario.com> [bvanassche: simplified implementation] Signed-off-by: Bart Van Assche <bvanassche@acm.org> git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5965 d57e44dd-8a1f-0410-8b47-8ef2f437770f
Overview ======== This is the SCST development repository. It contains not a single project SCST as one can think, but a number of them, which are divided as the following: 1. SCST core in scst/ subdirectory 2. Administration utility for SCST core scstadmin in scstadmin/ 3. Target drivers in own subdirectories qla2x00t/, iscsi-scst/, etc. 4. User space programs in usr/ subdirectory, like fileio_tgt. 5. Some various docs in doc/ subdirectory. Those subprojects are in most cases independent from each other, although some of them depend from the SCST core. They put in the single repository only to simplify their development, they are released independently. Thus, use "make all" only if you really need to build everything. Otherwise build only what you need, like for iSCSI-SCST: make scst scst_install iscsi iscsi_install For more information about each subproject see their README files. QLogic target driver ==================== QLogic target driver in qla2x00t/ is the old one, forked from qla2xxx from kernel 2.6.26. It is not maintained anymore and not built by default by the common Makefile targets, like "all". You can find the latest version of this driver in git://git.qlogic.com/scst-qla2xxx.git. It is now maintained by QLogic, hence located in the QLogic's git. To integrate it into the SCST build tree you need: 1. Clone the QLogic git tree somewhere in your system. 2. Create in the SCST root, i.e. this directory, a subdirectory with name qla2x00t_git 3. Symlink drivers/scsi/qla2xxx subdirectory in the cloned git tree to the qla2x00t_git subdirectory Thats all. Now "make all" and other common and QLA specific root Makefile targets "magically" start working. For detail instructions how to setup QLA target build environment see its README or HOWTO. You can still build the old driver using qla_old* root Makefile targets. Vladislav Bolkhovitin <vst@vlnb.net>, http://scst.sourceforge.net