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.. SPDX-License-Identifier: GPL-2.0
============================
Configurable Error Injection
============================
Overview
--------
Configurable error injection allows injecting specific block layer status codes
for sector ranges of a block device. Errors can be injected unconditionally, or
with a given probability.
To use configurable error injection, CONFIG_BLK_ERROR_INJECTION must be enabled.
The only interface is the error_injection debugfs file, which is created for
each registered gendisk. Writes to this file are used to create or delete rules
and reads return a list of the current error injection sites.
Options
-------
The following options specify the operations:
=================== =======================================================
add add a new rule
removeall remove all existing rules
=================== =======================================================
The following options specify the details of the rule for the add operation:
=================== =======================================================
op=<string> block layer operation this rule applies to. This uses
the XYZ for each REQ_OP_XYZ operation, e.g. READ, WRITE
or DISCARD. Mandatory.
status=<string> Status to return. This uses XYZ for each BLK_STS_XYZ
code, e.g. IOERR or MEDIUM. Mandatory.
start=<number> First block layer sector the rule applies to.
Optional, defaults to 0.
nr_sectors=<number> Number of sectors this rule applies.
Optional, defaults to the remainder of the device.
chance=<number> Only return a failure with a likelihood of 1/chance.
Optional, defaults to 1 (always).
=================== =======================================================
Example
-------
Return BLK_STS_IOERR for one in 10 reads of sector 0 of /dev/nvme0n1:
$ echo 'add,op=READ,start=0,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection
Return BLK_STS_MEDIUM for every write to /dev/nvme0n1:
$ echo 'add,op=WRITE,start=0,status=MEDIUM' > /sys/kernel/debug/block/nvme0n1/error_injection
Remove all rules for /dev/nvme0n1:
$ echo 'removeall' > /sys/kernel/debug/block/nvme0n1/error_injection
|
