From e02898b423802b1f3a3aaa7f16e896da069ba8f7 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Wed, 1 Mar 2017 10:42:38 -0800 Subject: [PATCH] loop: fix LO_FLAGS_PARTSCAN hang loop_reread_partitions() needs to do I/O, but we just froze the queue, so we end up waiting forever. This can easily be reproduced with losetup -P. Fix it by moving the reread to after we unfreeze the queue. Fixes: ecdd09597a57 ("block/loop: fix race between I/O and set_status") Reported-by: Tejun Heo Cc: stable@vger.kernel.org Signed-off-by: Omar Sandoval Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/block/loop.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 4b52a1690329..132c9f371dce 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1142,13 +1142,6 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) (info->lo_flags & LO_FLAGS_AUTOCLEAR)) lo->lo_flags ^= LO_FLAGS_AUTOCLEAR; - if ((info->lo_flags & LO_FLAGS_PARTSCAN) && - !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { - lo->lo_flags |= LO_FLAGS_PARTSCAN; - lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; - loop_reread_partitions(lo, lo->lo_device); - } - lo->lo_encrypt_key_size = info->lo_encrypt_key_size; lo->lo_init[0] = info->lo_init[0]; lo->lo_init[1] = info->lo_init[1]; @@ -1163,6 +1156,14 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) exit: blk_mq_unfreeze_queue(lo->lo_queue); + + if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) && + !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { + lo->lo_flags |= LO_FLAGS_PARTSCAN; + lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; + loop_reread_partitions(lo, lo->lo_device); + } + return err; }