On 02/22/2019 07:47 PM, Jan Kara wrote: > On Thu 21-02-19 23:33:43, Dongli Zhang wrote: >> Commit 0da03cab87e6 >> ("loop: Fix deadlock when calling blkdev_reread_part()") moves >> blkdev_reread_part() out of the loop_ctl_mutex. However, >> GENHD_FL_NO_PART_SCAN is set before __blkdev_reread_part(). As a result, >> __blkdev_reread_part() will fail the check of GENHD_FL_NO_PART_SCAN and >> will not rescan the loop device to delete all partitions. >> >> Below are steps to reproduce the issue: >> >> step1 # dd if=/dev/zero of=tmp.raw bs=1M count=100 >> step2 # losetup -P /dev/loop0 tmp.raw >> step3 # parted /dev/loop0 mklabel gpt >> step4 # parted -a none -s /dev/loop0 mkpart primary 64s 1 >> step5 # losetup -d /dev/loop0 >> >> Step5 will not be able to delete /dev/loop0p1 (introduced by step4) and >> there is below kernel warning message: >> >> [ 464.414043] __loop_clr_fd: partition scan of loop0 failed (rc=-22) >> >> This patch sets GENHD_FL_NO_PART_SCAN after blkdev_reread_part(). >> >> Fixes: 0da03cab87e6 ("loop: Fix deadlock when calling blkdev_reread_part()") >> Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx> >> --- >> Changed since v1: >> * move the setting of lo->lo_state to Lo_unbound after partscan has finished as well >> (suggested by Jan Kara) >> >> drivers/block/loop.c | 26 ++++++++++++++++++++++---- >> 1 file changed, 22 insertions(+), 4 deletions(-) > > Thanks the patch looks good! Just one nit below: > >> diff --git a/drivers/block/loop.c b/drivers/block/loop.c >> index 7908673..a13f5dc 100644 >> --- a/drivers/block/loop.c >> +++ b/drivers/block/loop.c >> @@ -1034,6 +1034,16 @@ loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer, >> return err; >> } >> >> +static void loop_disable_partscan(struct loop_device *lo) >> +{ > > I don't think there's any benefit in having this small function with a single > caller and furthermore with the subtle sideeffect that it changes lo_state. > So I'd just put the code inline in __loop_clr_fd(). With that you can add: > > Reviewed-by: Jan Kara <jack@xxxxxxx> Thank you very much! I will send out v3 with the Reviewed-by and put the code inline in __loop_clr_fd(). Dongli Zhang > > Honza >