1 files changed, 16 insertions, 5 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index b5e87896f517..897ee0503932 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -146,15 +146,13 @@ blkdev_get_block(struct inode *inode, sector_t iblock,
 }
 
 static ssize_t
-blkdev_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
-                        loff_t offset)
+blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
 {
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
 
-        return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iter,
-                                    offset, blkdev_get_block,
-                                    NULL, NULL, 0);
+        return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
+                                    blkdev_get_block, NULL, NULL, 0);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
@@ -1597,9 +1595,22 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
         struct file *file = iocb->ki_filp;
+        struct inode *bd_inode = file->f_mapping->host;
+        loff_t size = i_size_read(bd_inode);
         struct blk_plug plug;
         ssize_t ret;
 
+        if (bdev_read_only(I_BDEV(bd_inode)))
+                return -EPERM;
+
+        if (!iov_iter_count(from))
+                return 0;
+
+        if (iocb->ki_pos >= size)
+                return -ENOSPC;
+
+        iov_iter_truncate(from, size - iocb->ki_pos);
+
         blk_start_plug(&plug);
         ret = __generic_file_write_iter(iocb, from);
         if (ret > 0) {