Function | Error | Description
=========|==============|=============================================
open | -ENXIO | not a valid device
| -EACCES | access mode is not read/write (O_RDWR)
| -EBUSY | device was requested for nonblocking access,
| | but is busy now.
| -ERESTARTSYS | this indicates an internal error. Try to
| | make it reproducible and inform the SCSI
| | channel (for details on bug reporting
| | see Drew Eckhardts SCSI-HOWTO).
ioctl | -ENXIO | not a valid device
read | -EWOULDBLOCK | the device would block. Try again later.
write | -EIO | the length is too small (smaller than the
| | generic header struct). Caution: Currently
| | there is checking for lengths being too great
| -EWOULDBLOCK | the device would block. Try again later.
| -ERESTARTSYS | this indicates an internal error. Try to
| | make it reproducible and inform the SCSI
| | channel (for details on bug reporting
| | see Drew Eckhardts SCSI-HOWTO).
| -ENOMEM | memory required for this request could not be
| | allocated. Try later again unless you
| | exceeded the maximum transfer size (see above)
Positive values indicate as usual the amount of bytes that have been successfully transferred, which should equal the amount you requested.
Furthermore a detailed reporting is done via the kernels hd_status
and the devices reports in the sense_buffer (see
section
sec-sensebuff
) from the header structure.
The meaning of hd_status can be found in drivers/scsi/scsi.h:
This unsigned int is composed out of different parts:
lsb | ... | ... | msb
=======|===========|===========|============
status | sense key | host code | driver byte
These macros from drivers/scsi/scsi.h can be used to separate the
fields:
Macro | Description
====================|================================================
status_byte(result) | The SCSI device status. See above
msg_byte(result) | The devices sense key. See above
host_byte(result) | The host code from the kernel driver. See above
driver_byte(result) | The first byte from the device
The following status codes from the SCSI device
(defined in drivers/scsi/scsi.h)
should be used with the macro status_byte (see
section
sec-stat-decoding
):
Value | Symbol
======|=====================
0x00 | GOOD
0x01 | CHECK_CONDITION
0x02 | CONDITION_GOOD
0x04 | BUSY
0x08 | INTERMEDIATE_GOOD
0x0a | INTERMEDIATE_C_GOOD
0x0c | RESERVATION_CONFLICT
Note that these symbol values have been shifted right once. From the SCSI-2 specification:
Table 27: Status Byte Code
+=================================-==============================+
| Bits of Status Byte | Status |
| 7 6 5 4 3 2 1 0 | |
|---------------------------------+------------------------------|
| R R 0 0 0 0 0 R | GOOD |
| R R 0 0 0 0 1 R | CHECK CONDITION |
| R R 0 0 0 1 0 R | CONDITION MET |
| R R 0 0 1 0 0 R | BUSY |
| R R 0 1 0 0 0 R | INTERMEDIATE |
| R R 0 1 0 1 0 R | INTERMEDIATE-CONDITION MET |
| R R 0 1 1 0 0 R | RESERVATION CONFLICT |
| R R 1 0 0 0 1 R | COMMAND TERMINATED |
| R R 1 0 1 0 0 R | QUEUE FULL |
| | |
| All Other Codes | Reserved |
|----------------------------------------------------------------|
| Key: R = Reserved bit |
+================================================================+
A definition of the status byte codes is given below.
GOOD. This status indicates that the target has successfully completed the
command.
CHECK CONDITION. This status indicates that a contingent allegiance condition
has occurred (see 6.6).
CONDITION MET. This status or INTERMEDIATE-CONDITION MET is returned whenever
the requested operation is satisfied (see the SEARCH DATA and PRE-FETCH
commands).
BUSY. This status indicates that the target is busy. This status shall be
returned whenever a target is unable to accept a command from an otherwise
acceptable initiator (i.e., no reservation conflicts). The recommended
initiator recovery action is to issue the command again at a later time.
INTERMEDIATE. This status or INTERMEDIATE-CONDITION MET shall be returned for
every successfully completed command in a series of linked commands (except
the last command), unless the command is terminated with CHECK CONDITION,
RESERVATION CONFLICT, or COMMAND TERMINATED status. If INTERMEDIATE or
INTERMEDIATE-CONDITION MET status is not returned, the series of linked
commands is terminated and the I/O process is ended.
INTERMEDIATE-CONDITION MET. This status is the combination of the CONDITION
MET and INTERMEDIATE statuses.
RESERVATION CONFLICT. This status shall be returned whenever an initiator
attempts to access a logical unit or an extent within a logical unit that is
reserved with a conflicting reservation type for another SCSI device (see the
RESERVE and RESERVE UNIT commands). The recommended initiator recovery action
is to issue the command again at a later time.
COMMAND TERMINATED. This status shall be returned whenever the target
terminates the current I/O process after receiving a TERMINATE I/O PROCESS
message (see 5.6.22). This status also indicates that a contingent allegiance
condition has occurred (see 6.6).
QUEUE FULL. This status shall be implemented if tagged queuing is
implemented. This status is returned when a SIMPLE QUEUE TAG, ORDERED QUEUE
TAG, or HEAD OF QUEUE TAG message is received and the command queue is full.
The I/O process is not placed in the command queue.
The sense key from the result should be retrieved with the
macro msg_byte (see section
sec-stat-decoding
).
These kernel symbols (from drivers/scsi/scsi.h) are predefined:
Value | Symbol
======|================
0x00 | NO_SENSE
0x01 | RECOVERED_ERROR
0x02 | NOT_READY
0x03 | MEDIUM_ERROR
0x04 | HARDWARE_ERROR
0x05 | ILLEGAL_REQUEST
0x06 | UNIT_ATTENTION
0x07 | DATA_PROTECT
0x08 | BLANK_CHECK
0x0a | COPY_ABORTED
0x0b | ABORTED_COMMAND
0x0d | VOLUME_OVERFLOW
0x0e | MISCOMPARE
A verbatim list from the SCSI-2 doc follows (from section 7.2.14.3):
Table 69: Sense Key (0h-7h) Descriptions
+========-====================================================================+
| Sense | Description |
| Key | |
|--------+--------------------------------------------------------------------|
| 0h | NO SENSE. Indicates that there is no specific sense key |
| | information to be reported for the designated logical unit. This |
| | would be the case for a successful command or a command that |
| | received CHECK CONDITION or COMMAND TERMINATED status because one |
| | of the filemark, EOM, or ILI bits is set to one. |
|--------+--------------------------------------------------------------------|
| 1h | RECOVERED ERROR. Indicates that the last command completed |
| | successfully with some recovery action performed by the target. |
| | Details may be determinable by examining the additional sense |
| | bytes and the information field. When multiple recovered errors |
| | occur during one command, the choice of which error to report |
| | (first, last, most severe, etc.) is device specific. |
|--------+--------------------------------------------------------------------|
| 2h | NOT READY. Indicates that the logical unit addressed cannot be |
| | accessed. Operator intervention may be required to correct this |
| | condition. |
|--------+--------------------------------------------------------------------|
| 3h | MEDIUM ERROR. Indicates that the command terminated with a non- |
| | recovered error condition that was probably caused by a flaw in |
| | the medium or an error in the recorded data. This sense key may |
| | also be returned if the target is unable to distinguish between a |
| | flaw in the medium and a specific hardware failure (sense key 4h).|
|--------+--------------------------------------------------------------------|
| 4h | HARDWARE ERROR. Indicates that the target detected a non- |
| | recoverable hardware failure (for example, controller failure, |
| | device failure, parity error, etc.) while performing the command |
| | or during a self test. |
|--------+--------------------------------------------------------------------|
| 5h | ILLEGAL REQUEST. Indicates that there was an illegal parameter in|
| | the command descriptor block or in the additional parameters |
| | supplied as data for some commands (FORMAT UNIT, SEARCH DATA, |
| | etc.). If the target detects an invalid parameter in the command |
| | descriptor block, then it shall terminate the command without |
| | altering the medium. If the target detects an invalid parameter |
| | in the additional parameters supplied as data, then the target may|
| | have already altered the medium. This sense key may also indicate|
| | that an invalid IDENTIFY message was received (5.6.7). |
|--------+--------------------------------------------------------------------|
| 6h | UNIT ATTENTION. Indicates that the removable medium may have been|
| | changed or the target has been reset. See 6.9 for more detailed |
| | information about the unit attention condition. |
|--------+--------------------------------------------------------------------|
| 7h | DATA PROTECT. Indicates that a command that reads or writes the |
| | medium was attempted on a block that is protected from this |
| | operation. The read or write operation is not performed. |
+=============================================================================+
Table 70: Sense Key (8h-Fh) Descriptions
+========-====================================================================+
| Sense | Description |
| Key | |
|--------+--------------------------------------------------------------------|
| 8h | BLANK CHECK. Indicates that a write-once device or a sequential- |
| | access device encountered blank medium or format-defined end-of- |
| | data indication while reading or a write-once device encountered a|
| | non-blank medium while writing. |
|--------+--------------------------------------------------------------------|
| 9h | Vendor Specific. This sense key is available for reporting vendor|
| | specific conditions. |
|--------+--------------------------------------------------------------------|
| Ah | COPY ABORTED. Indicates a COPY, COMPARE, or COPY AND VERIFY |
| | command was aborted due to an error condition on the source |
| | device, the destination device, or both. (See 7.2.3.2 for |
| | additional information about this sense key.) |
|--------+--------------------------------------------------------------------|
| Bh | ABORTED COMMAND. Indicates that the target aborted the command. |
| | The initiator may be able to recover by trying the command again. |
|--------+--------------------------------------------------------------------|
| Ch | EQUAL. Indicates a SEARCH DATA command has satisfied an equal |
| | comparison. |
|--------+--------------------------------------------------------------------|
| Dh | VOLUME OVERFLOW. Indicates that a buffered peripheral device has |
| | reached the end-of-partition and data may remain in the buffer |
| | that has not been written to the medium. A RECOVER BUFFERED DATA |
| | command(s) may be issued to read the unwritten data from the |
| | buffer. |
|--------+--------------------------------------------------------------------|
| Eh | MISCOMPARE. Indicates that the source data did not match the data|
| | read from the medium. |
|--------+--------------------------------------------------------------------|
| Fh | RESERVED. |
+=============================================================================+
The following host codes are defined in drivers/scsi/scsi.h. They
are set by the kernel driver and should be used with the macro
host_byte (see section
sec-stat-decoding
):
Value | Symbol | Description
======|================|========================================
0x00 | DID_OK | No error
0x01 | DID_NO_CONNECT | Couldn't connect before timeout period
0x02 | DID_BUS_BUSY | BUS stayed busy through time out period
0x03 | DID_TIME_OUT | TIMED OUT for other reason
0x04 | DID_BAD_TARGET | BAD target
0x05 | DID_ABORT | Told to abort for some other reason
0x06 | DID_PARITY | Parity error
0x07 | DID_ERROR | internal error
0x08 | DID_RESET | Reset by somebody
0x09 | DID_BAD_INTR | Got an interrupt we weren't expecting
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