| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 067/153] loop: fix LO_FLAGS_PARTSCAN hang | Date | Fri, 10 Mar 2017 10:08:20 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Omar Sandoval <osandov@fb.com>
commit e02898b423802b1f3a3aaa7f16e896da069ba8f7 upstream.
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 <tj@kernel.org> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/block/loop.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)
--- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1142,13 +1142,6 @@ loop_set_status(struct loop_device *lo, (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, 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; }
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