[PATCH] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[PATCH] 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_SETSTATUS too.

Signed-off-by: Lennart Poettering <lennart@poettering.net>
---
 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] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Martijn Coenen]

Hi Lennart,

Thanks again for the patch, I tested it and it looks good to me. I'll
also add a test case to LTP for this. Two minor nits on the patch:

On Thu, Aug 6, 2020 at 9:32 AM Lennart Poettering <mzxreary@0pointer.de> wrote:
> Let's correct that and propagate the flag in LOOP_SETSTATUS too.

Think you meant LOOP_CONFIGURE.

Also, could you add a "Fixes" tag, like:

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


>
> Signed-off-by: Lennart Poettering <lennart@poettering.net>
> ---
>  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] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Lennart Poettering]

On Fr, 07.08.20 10:53, Martijn Coenen (maco@android.com) wrote:

> Hi Lennart,
>
> Thanks again for the patch, I tested it and it looks good to me. I'll
> also add a test case to LTP for this. Two minor nits on the patch:
>
> On Thu, Aug 6, 2020 at 9:32 AM Lennart Poettering <mzxreary@0pointer.de> wrote:
> > Let's correct that and propagate the flag in LOOP_SETSTATUS too.
>
> Think you meant LOOP_CONFIGURE.

True!

> Also, could you add a "Fixes" tag, like:
>
> Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")

Thanks for the review. I'll fix this up and send a v2. Are you OK with
me adding your Ack to the patch? And also should this geta cc for
stable?

Thanks,

Lennart

--
Lennart Poettering, Berlin

Re: [PATCH] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE

[Martijn Coenen]

On Fri, Aug 7, 2020 at 5:31 PM Lennart Poettering <mzxreary@0pointer.de> wrote:
> Thanks for the review. I'll fix this up and send a v2. Are you OK with
> me adding your Ack to the patch?

Yeah, sure!

> And also should this geta cc for stable?

LOOP_CONFIGURE was just added in v5.8, and stable is v5.7 now, so I
don't think that's needed.

Thanks,
Martijn

>
> Thanks,
>
> Lennart
>
> --
> Lennart Poettering, Berlin