1. 错误打印log
硬盘跑IO的时候，经常会见到下面这种错误log，这是SCSI做的打印。这是什么错误？该怎么定位？
[ 6304.176111] sd 0:0:4:0: [sde] tag#7 UNKNOWN(0x2003) Result: hostbyte=0x07 driverbyte=0x00 [ 6304.184281] sd 0:0:4:0: [sde] tag#7 CDB: opcode=0x28 28 00 00 0a 88 00 00 04 00 00 [ 6304.191838] print_req_error: I/O error, dev sde, sector 690176 [ 6333.587832] sd 0:0:4:0: [sde] tag#0 UNKNOWN(0x2003) Result: hostbyte=0x05 driverbyte=0x00 [ 6333.596010] sd 0:0:4:0: [sde] tag#0 CDB: opcode=0x28 28 00 00 0a 8c 00 00 04 00 00
2. log打印位置
首先，我们看这个日志是在哪里打印的。drivers/scsi/scsi_lib.c中scsi_io_completion()。两行分别对应scsi_print_result()和scsi_print_command()。
3. hostbyte和driverbyte含义
hostbyte和driverbyte是cmd->result中的域，如下所示。
hostbyte码值对应的含义如下：
132 /* 133 * Host byte codes 134 */ 135 136 #define DID_OK 0x00 /* NO error */ 137 #define DID_NO_CONNECT 0x01 /* Couldn't connect before timeout period */ 138 #define DID_BUS_BUSY 0x02 /* BUS stayed busy through time out period */ 139 #define DID_TIME_OUT 0x03 /* TIMED OUT for other reason */ 140 #define DID_BAD_TARGET 0x04 /* BAD target. */ 141 #define DID_ABORT 0x05 /* Told to abort for some other reason */ 142 #define DID_PARITY 0x06 /* Parity error */ 143 #define DID_ERROR 0x07 /* Internal error */ 144 #define DID_RESET 0x08 /* Reset by somebody. */ 145 #define DID_BAD_INTR 0x09 /* Got an interrupt we weren't expecting. */ 146 #define DID_PASSTHROUGH 0x0a /* Force command past mid-layer */ 147 #define DID_SOFT_ERROR 0x0b /* The low level driver just wish a retry */ 148 #define DID_IMM_RETRY 0x0c /* Retry without decrementing retry count */ 149 #define DID_REQUEUE 0x0d /* Requeue command (no immediate retry) also 150 * without decrementing the retry count */ 151 #define DID_TRANSPORT_DISRUPTED 0x0e /* Transport error disrupted execution 152 * and the driver blocked the port to 153 * recover the link. Transport class will 154 * retry or fail IO */ 155 #define DID_TRANSPORT_FAILFAST 0x0f /* Transport class fastfailed the io */ 156 #define DID_TARGET_FAILURE 0x10 /* Permanent target failure, do not retry on 157 * other paths */ 158 #define DID_NEXUS_FAILURE 0x11 /* Permanent nexus failure, retry on other 159 * paths might yield different results */ 160 #define DID_ALLOC_FAILURE 0x12 /* Space allocation on the device failed */ 161 #define DID_MEDIUM_ERROR 0x13 /* Medium error */
4. hostbyte跟底层的转换关系
SAS_ABORTED_TASK --> DID_ABORT