release/4.8.25/nbd-use-loff_t-for-blocksize-and-nbd_set_size-args.patch

From be7b1c46fa4033879ea7c85726f58b7370995b71 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fb.com>
Date: Fri, 2 Dec 2016 16:19:12 -0500
Subject: [PATCH] nbd: use loff_t for blocksize and nbd_set_size args

commit ef77b515243b3499d62cf446eda6ca7e0a0b079c upstream.

If we have large devices (say like the 40t drive I was trying to test with) we
will end up overflowing the int arguments to nbd_set_size and not get the right
size for our device.  Fix this by using loff_t everywhere so I don't have to
think about this again.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index a9e398019f38..90a4142d6ece 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -54,7 +54,7 @@ struct nbd_device {
 
 	struct mutex tx_lock;
 	struct gendisk *disk;
-	int blksize;
+	loff_t blksize;
 	loff_t bytesize;
 	int xmit_timeout;
 	bool timedout;
@@ -137,7 +137,7 @@ static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
 }
 
 static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
-			int blocksize, int nr_blocks)
+			loff_t blocksize, loff_t nr_blocks)
 {
 	int ret;
 
@@ -146,7 +146,7 @@ static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
 		return ret;
 
 	nbd->blksize = blocksize;
-	nbd->bytesize = (loff_t)blocksize * (loff_t)nr_blocks;
+	nbd->bytesize = blocksize * nr_blocks;
 
 	nbd_size_update(nbd, bdev);
 
@@ -936,7 +936,7 @@ static int nbd_dev_dbg_init(struct nbd_device *nbd)
 	debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
 	debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);
 	debugfs_create_u32("timeout", 0444, dir, &nbd->xmit_timeout);
-	debugfs_create_u32("blocksize", 0444, dir, &nbd->blksize);
+	debugfs_create_u64("blocksize", 0444, dir, &nbd->blksize);
 	debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
 
 	return 0;
-- 
2.12.0