diff mbox series

loop: Fix missing discard support when using LOOP_CONFIGURE

Message ID 20210617221158.7045-1-kristian@klausen.dk (mailing list archive)
State New, archived
Headers show
Series loop: Fix missing discard support when using LOOP_CONFIGURE | expand

Commit Message

Kristian Klausen June 17, 2021, 10:11 p.m. UTC 
Cc: <stable@vger.kernel.org> # 5.8.x-
Fixes: 3448914e8cc5 ("loop: Add LOOP_CONFIGURE ioctl")
Signed-off-by: Kristian Klausen <kristian@klausen.dk>
---
Tested like so (without the patch):
losetup 2.37<= uses LOOP_CONFIGURE instead of LOOP_SET_STATUS64[1]

# fallocate -l100M disk.img
# rmmod loop
# losetup --version
losetup from util-linux 2.36.2
# losetup --find --show disk.img
/dev/loop0
# grep '' /sys/devices/virtual/block/loop0/queue/*discard*
/sys/devices/virtual/block/loop0/queue/discard_granularity:4096
/sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
/sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
/sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
/sys/devices/virtual/block/loop0/queue/max_discard_segments:1
# losetup -d /dev/loop0
# [update util-linux]
# losetup --version
losetup from util-linux 2.37
# rmmod loop
# losetup --find --show disk.img
/dev/loop0
# grep '' /sys/devices/virtual/block/loop0/queue/*discard*
/sys/devices/virtual/block/loop0/queue/discard_granularity:0
/sys/devices/virtual/block/loop0/queue/discard_max_bytes:0
/sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:0
/sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
/sys/devices/virtual/block/loop0/queue/max_discard_segments:1


With the patch applied:

# losetup --version
losetup from util-linux 2.37
# rmmod loop
# losetup --find --show disk.img
/dev/loop0
# grep '' /sys/devices/virtual/block/loop0/queue/*discard*
/sys/devices/virtual/block/loop0/queue/discard_granularity:4096
/sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
/sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
/sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
/sys/devices/virtual/block/loop0/queue/max_discard_segments:1

[1] https://github.com/karelzak/util-linux/pull/1152

 drivers/block/loop.c | 2 ++
 1 file changed, 2 insertions(+)


base-commit: 70585216fe7730d9fb5453d3e2804e149d0fe201

Comments

Ming Lei June 17, 2021, 11:03 p.m. UTC | #1 
On Fri, Jun 18, 2021 at 12:11:57AM +0200, Kristian Klausen wrote:

Commit log?

> Cc: <stable@vger.kernel.org> # 5.8.x-
> Fixes: 3448914e8cc5 ("loop: Add LOOP_CONFIGURE ioctl")
> Signed-off-by: Kristian Klausen <kristian@klausen.dk>
> ---
> Tested like so (without the patch):
> losetup 2.37<= uses LOOP_CONFIGURE instead of LOOP_SET_STATUS64[1]
> 
> # fallocate -l100M disk.img
> # rmmod loop
> # losetup --version
> losetup from util-linux 2.36.2
> # losetup --find --show disk.img
> /dev/loop0
> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
> /sys/devices/virtual/block/loop0/queue/discard_granularity:4096
> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
> # losetup -d /dev/loop0
> # [update util-linux]
> # losetup --version
> losetup from util-linux 2.37
> # rmmod loop
> # losetup --find --show disk.img
> /dev/loop0
> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
> /sys/devices/virtual/block/loop0/queue/discard_granularity:0
> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:0
> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:0
> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
> 
> 
> With the patch applied:
> 
> # losetup --version
> losetup from util-linux 2.37
> # rmmod loop
> # losetup --find --show disk.img
> /dev/loop0
> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
> /sys/devices/virtual/block/loop0/queue/discard_granularity:4096
> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
> 
> [1] https://github.com/karelzak/util-linux/pull/1152
> 
>  drivers/block/loop.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 76e12f3482a9..ec957f6d8a49 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1168,6 +1168,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  	if (partscan)
>  		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
>  
> +	loop_config_discard(lo);
> +

It could be better to move loop_config_discard() around
loop_update_rotational/loop_update_dio(), then we setup everything
before updating loop as Lo_bound.

Otherwise, this patch looks fine.


Thanks,
Ming
Kristian Klausen June 17, 2021, 11:26 p.m. UTC | #2 
On 18.06.2021 01.03, Ming Lei wrote:
> On Fri, Jun 18, 2021 at 12:11:57AM +0200, Kristian Klausen wrote:
>
> Commit log?

I will try to come up with a commit message. AFAIU the missing call to 
loop_config_discard() causes the block device to report "no discard 
support" (best-case) or stale/incorrect discard support (ex: if the loop 
device was configured with LOOP_SET_STATUS(64) and later LOOP_CONFIGURE).

>
>> Cc: <stable@vger.kernel.org> # 5.8.x-
>> Fixes: 3448914e8cc5 ("loop: Add LOOP_CONFIGURE ioctl")
>> Signed-off-by: Kristian Klausen <kristian@klausen.dk>
>> ---
>> Tested like so (without the patch):
>> losetup 2.37<= uses LOOP_CONFIGURE instead of LOOP_SET_STATUS64[1]
>>
>> # fallocate -l100M disk.img
>> # rmmod loop
>> # losetup --version
>> losetup from util-linux 2.36.2
>> # losetup --find --show disk.img
>> /dev/loop0
>> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
>> /sys/devices/virtual/block/loop0/queue/discard_granularity:4096
>> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
>> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
>> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
>> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
>> # losetup -d /dev/loop0
>> # [update util-linux]
>> # losetup --version
>> losetup from util-linux 2.37
>> # rmmod loop
>> # losetup --find --show disk.img
>> /dev/loop0
>> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
>> /sys/devices/virtual/block/loop0/queue/discard_granularity:0
>> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:0
>> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:0
>> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
>> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
>>
>>
>> With the patch applied:
>>
>> # losetup --version
>> losetup from util-linux 2.37
>> # rmmod loop
>> # losetup --find --show disk.img
>> /dev/loop0
>> # grep '' /sys/devices/virtual/block/loop0/queue/*discard*
>> /sys/devices/virtual/block/loop0/queue/discard_granularity:4096
>> /sys/devices/virtual/block/loop0/queue/discard_max_bytes:4294966784
>> /sys/devices/virtual/block/loop0/queue/discard_max_hw_bytes:4294966784
>> /sys/devices/virtual/block/loop0/queue/discard_zeroes_data:0
>> /sys/devices/virtual/block/loop0/queue/max_discard_segments:1
>>
>> [1] https://github.com/karelzak/util-linux/pull/1152
>>
>>   drivers/block/loop.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
>> index 76e12f3482a9..ec957f6d8a49 100644
>> --- a/drivers/block/loop.c
>> +++ b/drivers/block/loop.c
>> @@ -1168,6 +1168,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>>   	if (partscan)
>>   		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
>>   
>> +	loop_config_discard(lo);
>> +
> It could be better to move loop_config_discard() around
> loop_update_rotational/loop_update_dio(), then we setup everything
> before updating loop as Lo_bound.

I will move it before loop_update_rotational().

>
> Otherwise, this patch looks fine.
>
>
> Thanks,
> Ming
>
diff mbox series

Patch

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 76e12f3482a9..ec957f6d8a49 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1168,6 +1168,8 @@  static int loop_configure(struct loop_device *lo, fmode_t mode,
 	if (partscan)
 		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
 
+	loop_config_discard(lo);
+
 	/* Grab the block_device to prevent its destruction after we
 	 * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev).
 	 */