On Thu, Jan 30, 2020 at 03:10:42PM +0300, Konstantin Khlebnikov wrote:

Please consider including into 4.19 upstream commits

ba5d73851e71847ba7f7f4c27a1a6e1f5ab91c79 ("block: cleanup __blkdev_issue_discard()")

and

4800bf7bc8c725e955fcbc6191cc872f43f506d3 ("block: fix 32 bit overflow in __blkdev_issue_discard()")

THis patch does not apply to the 4.19 tree :(

Overflow of unsigned long "req_sects" (fixed in second patch) actually exist here much longer.

And 4.19 commit 744889b7cbb56a64f957e65ade7cb65fe3f35714 ("block: don't deal with discard limit in blkdev_issue_discard()") make it worse by replacing

req_sects = min_t(sector_t, nr_sects, q->limits.max_discard_sectors);

with

unsigned int req_sects = nr_sects;

because now discard length isn't cut by max_discard_sectors it easily overflows. As a result BLKDISCARD fails unexpectedly:

ioctl(3, BLKDISCARD, [0, 0x20000000000]) = -1 EOPNOTSUPP (Operation not supported)

I don't understand. Can you provide backported and working patches for the 4.19.y series so that I can apply them that way to show exactly what you have changed here?

thanks,

greg k-h