[PATCH blktests] common/null_blk: check FULL file availability before write

[PATCH blktests] common/null_blk: check FULL file availability before write

[Shin'ichiro Kawasaki]

Commit e2805c7911a4 ("common/null_blk: Log null_blk configuration
parameters") introduced the write to the $FULL file in
_configure_null_blk(). However, the $FULL file is not available when
_configure_null_blk() is called in the fallback_device() context. In
this case, the write fails with the error "No such file or directory".
To avoid the error, confirm that $FULL is available before write to it.

Fixes: e2805c7911a4 ("common/null_blk: Log null_blk configuration parameters")
Link: https://github.com/linux-blktests/blktests/issues/187
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
---
 common/null_blk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/common/null_blk b/common/null_blk
index 83f508f..7395754 100644
--- a/common/null_blk
+++ b/common/null_blk
@@ -64,7 +64,7 @@ _configure_null_blk() {
 	fi
 	params+=("$@")
 
-	echo "$nullb_path ${params[*]}" >>"${FULL}"
+	[[ -n "${FULL}" ]] && echo "$nullb_path ${params[*]}" >>"${FULL}"
 
 	for param in "${params[@]}"; do
 		local key="${param%%=*}" val="${param#*=}"
-- 
2.50.0

Re: [PATCH blktests] common/null_blk: check FULL file availability before write

[Yi Zhang]

Tested-by: Yi Zhang <yi.zhang@redhat.com>

# ./check zbd/001
common/null_blk: line 67: : No such file or directory
zbd/001 => nullb1 (sysfs and ioctl)                          [passed]
    runtime    ...  0.167s
With the patch
# ./check zbd/001
zbd/001 => nullb1 (sysfs and ioctl)                          [passed]
    runtime  0.167s  ...  0.174s

On Fri, Jul 4, 2025 at 6:54 PM Shin'ichiro Kawasaki
<shinichiro.kawasaki@wdc.com> wrote:
>
> Commit e2805c7911a4 ("common/null_blk: Log null_blk configuration
> parameters") introduced the write to the $FULL file in
> _configure_null_blk(). However, the $FULL file is not available when
> _configure_null_blk() is called in the fallback_device() context. In
> this case, the write fails with the error "No such file or directory".
> To avoid the error, confirm that $FULL is available before write to it.
>
> Fixes: e2805c7911a4 ("common/null_blk: Log null_blk configuration parameters")
> Link: https://github.com/linux-blktests/blktests/issues/187
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Suggested-by: Bart Van Assche <bvanassche@acm.org>
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> ---
>  common/null_blk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/common/null_blk b/common/null_blk
> index 83f508f..7395754 100644
> --- a/common/null_blk
> +++ b/common/null_blk
> @@ -64,7 +64,7 @@ _configure_null_blk() {
>         fi
>         params+=("$@")
>
> -       echo "$nullb_path ${params[*]}" >>"${FULL}"
> +       [[ -n "${FULL}" ]] && echo "$nullb_path ${params[*]}" >>"${FULL}"
>
>         for param in "${params[@]}"; do
>                 local key="${param%%=*}" val="${param#*=}"
> --
> 2.50.0
>
>


-- 
Best Regards,
  Yi Zhang

Re: [PATCH blktests] common/null_blk: check FULL file availability before write

[Bart Van Assche]

On 7/4/25 3:54 AM, Shin'ichiro Kawasaki wrote:
> Commit e2805c7911a4 ("common/null_blk: Log null_blk configuration
> parameters") introduced the write to the $FULL file in
> _configure_null_blk(). However, the $FULL file is not available when
> _configure_null_blk() is called in the fallback_device() context. In
> this case, the write fails with the error "No such file or directory".
> To avoid the error, confirm that $FULL is available before write to it.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Re: [PATCH blktests] common/null_blk: check FULL file availability before write

[Shinichiro Kawasaki]

On Jul 04, 2025 / 19:54, Shin'ichiro Kawasaki wrote:
> Commit e2805c7911a4 ("common/null_blk: Log null_blk configuration
> parameters") introduced the write to the $FULL file in
> _configure_null_blk(). However, the $FULL file is not available when
> _configure_null_blk() is called in the fallback_device() context. In
> this case, the write fails with the error "No such file or directory".
> To avoid the error, confirm that $FULL is available before write to it.
> 
> Fixes: e2805c7911a4 ("common/null_blk: Log null_blk configuration parameters")
> Link: https://github.com/linux-blktests/blktests/issues/187
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Suggested-by: Bart Van Assche <bvanassche@acm.org>
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

FYI, I have applied this patch.