The first error injection example is introduced as failing one in ten
reads of sector 0, but the rule it shows does not set nr_sectors, which
defaults to the remainder of the device.  As written it fails one in ten
reads of the whole device.

Add nr_sectors=1 so that the rule does what the text says.  This also
gives the documentation one example that uses nr_sectors.

Fixes: e8dcf2d142bd ("block: add configurable error injection")
Signed-off-by: Md Haris Iqbal <haris.iqbal@linux.dev>
---
 Documentation/block/error-injection.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/block/error-injection.rst b/Documentation/block/error-injection.rst
--- a/Documentation/block/error-injection.rst
+++ b/Documentation/block/error-injection.rst
@@ -48,7 +48,7 @@ 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
+	$ echo 'add,op=READ,start=0,nr_sectors=1,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection
 
 Return BLK_STS_MEDIUM for every write to /dev/nvme0n1:
 
--
2.53.0

在 2026/8/16 03:11, Md Haris Iqbal 写道:
> The first error injection example is introduced as failing one in ten
> reads of sector 0, but the rule it shows does not set nr_sectors, which
> defaults to the remainder of the device.  As written it fails one in ten
> reads of the whole device.
> 
> Add nr_sectors=1 so that the rule does what the text says.  This also
> gives the documentation one example that uses nr_sectors.
> 
> Fixes: e8dcf2d142bd ("block: add configurable error injection")
> Signed-off-by: Md Haris Iqbal <haris.iqbal@linux.dev>
> ---
>  Documentation/block/error-injection.rst | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/block/error-injection.rst b/Documentation/block/error-injection.rst
> --- a/Documentation/block/error-injection.rst
> +++ b/Documentation/block/error-injection.rst
> @@ -48,7 +48,7 @@ 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
> +	$ echo 'add,op=READ,start=0,nr_sectors=1,status=IOERR,chance=10' > /sys/kernel/debug/block/nvme0n1/error_injection
>  
>  Return BLK_STS_MEDIUM for every write to /dev/nvme0n1:
>  
> --
> 2.53.0
> 
> 
Reviewed-by: Tao Cui <cuitao@kylinos.cn>

On Sat, Aug 15, 2026 at 09:11:00PM +0200, Md Haris Iqbal wrote:
> The first error injection example is introduced as failing one in ten
> reads of sector 0, but the rule it shows does not set nr_sectors, which
> defaults to the remainder of the device.  As written it fails one in ten
> reads of the whole device.
> 
> Add nr_sectors=1 so that the rule does what the text says.  This also
> gives the documentation one example that uses nr_sectors.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>