The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b40813ddcd6bf9f01d020804e4cb8febc480b9e4 Mon Sep 17 00:00:00 2001
From: Ming Lei ming.lei@redhat.com Date: Wed, 28 Oct 2020 15:24:34 +0800 Subject: [PATCH] nbd: don't update block size after device is started
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@vger.kernel.org Fixes: c8a83a6b54d0 ("nbd: Use set_blocksize() to set device blocksize") Reported-by: lining lining2020x@163.com Signed-off-by: Ming Lei ming.lei@redhat.com Cc: Josef Bacik josef@toxicpanda.com Cc: Jan Kara jack@suse.cz Tested-by: lining lining2020x@163.com Signed-off-by: Jens Axboe axboe@kernel.dk
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 0bed21c0c81b..c4f9ccf5cc2a 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); @@ -313,7 +313,8 @@ static void nbd_size_update(struct nbd_device *nbd) if (bdev) { if (bdev->bd_disk) { bd_set_nr_sectors(bdev, nr_sectors); - set_blocksize(bdev, config->blksize); + if (start) + set_blocksize(bdev, config->blksize); } else set_bit(GD_NEED_PART_SCAN, &nbd->disk->state); bdput(bdev); @@ -328,7 +329,7 @@ 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) @@ -1308,7 +1309,7 @@ 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; }