Messages in this thread | | | Subject | Re: [PATCH] loop: Fix missing discard support when using LOOP_CONFIGURE | From | Kristian Klausen <> | Date | Fri, 18 Jun 2021 01:26:19 +0200 |
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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 >
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