On Fri, Apr 01, 2022 at 03:24:36PM +0530, Ritesh Harjani wrote: > On 22/04/01 11:27AM, Ojaswin Mujoo wrote: > > A recent ext4 patch discussed [1] that some devices (eg LVMs) can > > have a discard granularity as big as 42MB which makes it larger > > than the group size of ext4 FS with 1k BS. This causes the FITRIM > > IOCTL to fail on filesystems like ext4. > > > > This case was not correctly handle by "_require_batched_discard" as > > it incorrectly interpreted the FITRIM failure as fs not supporting > > the IOCTL. This caused the tests like generic/260 to incorectly > > report "not run" instead of "failed" in case of large discard > > granularity. > > Ok, I looked at fstrim code and it does print [1] > "the discard operation is not supported" in case of rc == 1. > And if rc != 0 it will always returns EXIT_FAILURE. > > So this patch looks good to me. Feel free to add: > > Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx> Thank you for the review Ritesh. > > > Although it will be good to check if we can add a generic test case > using maybe lvm or dm device, where this device could report large > discard_granularity for actually excercising this code path > (rather then changing kernel code to test it). You are correct, as I was not able to simulate a device with disc gran of 40MB+ I tested this by hard coding the granularity in the kernel. That being said, I would appreciate if anyone has any insights on using LVM/DM to get that high a granularity so I can test it more accurately. Regards, Ojaswin > > -ritesh > > [1]: https://github.com/util-linux/util-linux/blob/master/sys-utils/fstrim.c > > > > > Fix "_require_batched_discard" to use a more accurate method > > to determine if discard is supported. > > > > [1] commit 173b6e383d2 > > ext4: avoid trim error on fs with small groups > > > > Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx> > > --- > > common/rc | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > >
