[PATCH v2] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[PATCH v2] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Lennart Poettering]

When LOOP_CONFIGURE is used with LO_FLAGS_PARTSCAN we need to propagate
this into the GENHD_FL_NO_PART_SCAN. LOOP_SETSTATUS does this,
LOOP_CONFIGURE doesn't so far. Effect is that setting up a loopback
device with partition scanning doesn't actually work when LOOP_CONFIGURE
is issued, though it works fine with LOOP_SETSTATUS.

Let's correct that and propagate the flag in LOOP_CONFIGURE too.

Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")

Signed-off-by: Lennart Poettering <lennart@poettering.net>
Acked-by: Martijn Coenen <maco@android.com>
---
 drivers/block/loop.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d18160146226..2f137d6ce169 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1171,6 +1171,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	if (part_shift)
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
 	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
+	if (partscan)
+		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;

 	/* Grab the block_device to prevent its destruction after we
 	 * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev).
--
2.26.2

Re: [PATCH v2] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Martijn Coenen]

On Mon, Aug 10, 2020 at 7:16 PM Lennart Poettering <mzxreary@0pointer.de> wrote:
>
> When LOOP_CONFIGURE is used with LO_FLAGS_PARTSCAN we need to propagate
> this into the GENHD_FL_NO_PART_SCAN. LOOP_SETSTATUS does this,
> LOOP_CONFIGURE doesn't so far. Effect is that setting up a loopback
> device with partition scanning doesn't actually work when LOOP_CONFIGURE
> is issued, though it works fine with LOOP_SETSTATUS.
>
> Let's correct that and propagate the flag in LOOP_CONFIGURE too.
>
> Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")
>
> Signed-off-by: Lennart Poettering <lennart@poettering.net>
> Acked-by: Martijn Coenen <maco@android.com>

Thanks, still looks good to me.

> ---
>  drivers/block/loop.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index d18160146226..2f137d6ce169 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1171,6 +1171,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>         if (part_shift)
>                 lo->lo_flags |= LO_FLAGS_PARTSCAN;
>         partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
> +       if (partscan)
> +               lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
>
>         /* Grab the block_device to prevent its destruction after we
>          * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev).
> --
> 2.26.2

Re: [PATCH v2] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Jens Axboe]

On 8/11/20 12:49 AM, Martijn Coenen wrote:
> On Mon, Aug 10, 2020 at 7:16 PM Lennart Poettering <mzxreary@0pointer.de> wrote:
>>
>> When LOOP_CONFIGURE is used with LO_FLAGS_PARTSCAN we need to propagate
>> this into the GENHD_FL_NO_PART_SCAN. LOOP_SETSTATUS does this,
>> LOOP_CONFIGURE doesn't so far. Effect is that setting up a loopback
>> device with partition scanning doesn't actually work when LOOP_CONFIGURE
>> is issued, though it works fine with LOOP_SETSTATUS.
>>
>> Let's correct that and propagate the flag in LOOP_CONFIGURE too.
>>
>> Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")
>>
>> Signed-off-by: Lennart Poettering <lennart@poettering.net>
>> Acked-by: Martijn Coenen <maco@android.com>
> 
> Thanks, still looks good to me.

Applied.

-- 
Jens Axboe