Merge tag 'pull-set_blocksize' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs blocksize updates from Al Viro:
 "This gets rid of bogus set_blocksize() uses, switches it over
  to be based on a 'struct file *' and verifies that the caller
  has the device opened exclusively"

* tag 'pull-set_blocksize' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make set_blocksize() fail unless block device is opened exclusive
  set_blocksize(): switch to passing struct file *
  btrfs_get_bdev_and_sb(): call set_blocksize() only for exclusive opens
  swsusp: don't bother with setting block size
  zram: don't bother with reopening - just use O_EXCL for open
  swapon(2): open swap with O_EXCL
  swapon(2)/swapoff(2): don't bother with block size
  pktcdvd: sort set_blocksize() calls out
  bcache_register(): don't bother with set_blocksize()

1 files changed, 12 insertions, 9 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index c7db3bd2d653..615b6003fbb5 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -503,11 +503,14 @@ static int compat_hdio_getgeo(struct block_device *bdev,
 #endif
 
 /* set the logical block size */
-static int blkdev_bszset(struct block_device *bdev, blk_mode_t mode,
+static int blkdev_bszset(struct file *file, blk_mode_t mode,
 		int __user *argp)
 {
+	// this one might be file_inode(file)->i_rdev - a rare valid
+	// use of file_inode() for those.
+	dev_t dev = I_BDEV(file->f_mapping->host)->bd_dev;
+	struct file *excl_file;
 	int ret, n;
-	struct file *file;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
@@ -517,13 +520,13 @@ static int blkdev_bszset(struct block_device *bdev, blk_mode_t mode,
 		return -EFAULT;
 
 	if (mode & BLK_OPEN_EXCL)
-		return set_blocksize(bdev, n);
+		return set_blocksize(file, n);
 
-	file = bdev_file_open_by_dev(bdev->bd_dev, mode, &bdev, NULL);
-	if (IS_ERR(file))
+	excl_file = bdev_file_open_by_dev(dev, mode, &dev, NULL);
+	if (IS_ERR(excl_file))
 		return -EBUSY;
-	ret = set_blocksize(bdev, n);
-	fput(file);
+	ret = set_blocksize(excl_file, n);
+	fput(excl_file);
 	return ret;
 }
 
@@ -652,7 +655,7 @@ long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 		return put_int(argp, block_size(bdev));
 	case BLKBSZSET:
-		return blkdev_bszset(bdev, mode, argp);
+		return blkdev_bszset(file, mode, argp);
 	case BLKGETSIZE64:
 		return put_u64(argp, bdev_nr_bytes(bdev));
 
@@ -712,7 +715,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	case BLKBSZGET_32: /* get the logical block size (cf. BLKSSZGET) */
 		return put_int(argp, bdev_logical_block_size(bdev));
 	case BLKBSZSET_32:
-		return blkdev_bszset(bdev, mode, argp);
+		return blkdev_bszset(file, mode, argp);
 	case BLKGETSIZE64_32:
 		return put_u64(argp, bdev_nr_bytes(bdev));