This is a note to let you know that I've just added the patch titled nbd: don't update block size after device is started to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nbd-don-t-update-block-size-after-device-is-started.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 80d138ac02a0858d064a435d9e552a87c179d710 Author: Ming Lei <ming.lei@xxxxxxxxxx> Date: Wed Oct 28 15:24:34 2020 +0800 nbd: don't update block size after device is started [ Upstream commit b40813ddcd6bf9f01d020804e4cb8febc480b9e4 ] Mounted NBD device can be resized, one use case is rbd-nbd. Fix the issue by setting up default block size, then not touch it in nbd_size_update() any more. This kind of usage is aligned with loop which has same use case too. Cc: stable@xxxxxxxxxxxxxxx Fixes: c8a83a6b54d0 ("nbd: Use set_blocksize() to set device blocksize") Reported-by: lining <lining2020x@xxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> Cc: Josef Bacik <josef@xxxxxxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Tested-by: lining <lining2020x@xxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index f46e26c9d9b3c..d76fca629c143 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -296,7 +296,7 @@ static void nbd_size_clear(struct nbd_device *nbd) } } -static void nbd_size_update(struct nbd_device *nbd) +static void nbd_size_update(struct nbd_device *nbd, bool start) { struct nbd_config *config = nbd->config; struct block_device *bdev = bdget_disk(nbd->disk, 0); @@ -312,7 +312,8 @@ static void nbd_size_update(struct nbd_device *nbd) if (bdev) { if (bdev->bd_disk) { bd_set_size(bdev, config->bytesize); - set_blocksize(bdev, config->blksize); + if (start) + set_blocksize(bdev, config->blksize); } else bdev->bd_invalidated = 1; bdput(bdev); @@ -327,7 +328,7 @@ static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize, config->blksize = blocksize; config->bytesize = blocksize * nr_blocks; if (nbd->task_recv != NULL) - nbd_size_update(nbd); + nbd_size_update(nbd, false); } static void nbd_complete_rq(struct request *req) @@ -1307,7 +1308,7 @@ static int nbd_start_device(struct nbd_device *nbd) args->index = i; queue_work(nbd->recv_workq, &args->work); } - nbd_size_update(nbd); + nbd_size_update(nbd, true); return error; }